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In the present study, ohmic heating system was developed for the pasteurization of liquid egg white. A batch reactor system was designed with a capacity of 100 ml and operated at varied gradients of voltage (20, 15, 10 V/cm), frequencies (10, 55, 100 Hz), holding times (1, 2.5, 4 min) at two different waveforms (sine and square). The treated liquid egg white was evaluated for validation parameters viz., heating rate, turbidity, soluble protein content, foaming capacity, and foaming stability. The viscosity of ohmically treated egg white was observed by subjecting the egg white to the shear rate ranges from 0.167 to 68 (s−1) where the viscosity decreased as the shear rate increased. The ohmic heating process variables were optimized using the Box-Behnken design and had a significant effect (P < 0.005) on the responses. The optimized parameters 17.93 V/cm voltage gradient, 10 Hz frequency, and 1.6 min holding time for sine waveform resulted in 19.6 °C/min heating rate, 0.01 turbidity, 98.35% soluble protein, 405.68% foaming capacity, and 31.84% foaming stability with the highest desirability of 78% of liquid egg white. The model developed from the dataset of this design can be used for predicting the responses within the limits of process variables. [ABSTRACT FROM AUTHOR]

This work presents a way to use ethanol and spent coffee grounds (SCG) as feedstocks for biodiesel production to solve ethanol overproduction in Thailand and biodiesel feedstock shortage problems together. Waste coffee oil (SCGO) was ethanolic extracted from SCG; then, ethanol-SCGO mixture was transesterified in supercritical condition without ethanol removal. The ethanolic extraction curves of SCG at a temperature range of 50–70 °C were constructed. Transesterification experiments were studied in a batch reactor and a continuous reactor at various temperatures (275–350 °C) and reaction time (5–40 min) under 15.0 MPa. The molar ratio of ethanol-oil mixture was set at 30:1. The highest ester content of 88.37 ± 3.00 wt% was found in biodiesel obtained at a temperature of 275 °C and a reaction time of 40 min in a batch reactor. Furthermore, excess temperature (< 300 °C) and reaction time (< 20 min) induced thermal degradation and promoted the loss of ethyl linoleate. For continuous reactor, the maximum ester content of 83.38 ± 5.86 wt% was observed at 325 °C and 29.4 min of residence time. Unlike in batch reactors, thermal degradation of ethyl linoleate was not observed in a continuous reactor. The results showed that ethanolic extraction and supercritical transesterification are alternative ways to produce biodiesel from SCG without removing extractant and using catalyst. From a prospective point of view, techno-economic analysis (TEA) and life-cycle assessment (LCA) of invented process should be conducted to ensure profitability and environmental benefits, respectively. [ABSTRACT FROM AUTHOR]

Substantial amounts of expired dairy products (EDP) are generated due to their high perishability. These wastes are rich in organic matter, and their landfill disposal negatively impacts the environment. An alternative to reducing and recovering this waste would be to use it as a substrate in anaerobic digestion (AD) to produce biogas. This study investigated methane (CH4) production using different concentrations of EDP co-digested with synthetic domestic wastewater (SDW). Five anaerobic batch reactors (1000 mL) were assembled with different concentrations of EDP in SDW (500 mL working volume), namely (1) 0%, (2) 5.0%, (3) 7.5%, (4) 10.0%, and (5) 15.0% (v/v). COD removals were 81%, 84%, 80%, 89%, and 14% for assays 1 to 5, respectively. The cumulative CH4 productions were (mL/L) 717, 3354, 5327, 6584, and 1156 for assays 1 to 5, respectively. Assay 5 (15% EDP) was inhibited by volatile fatty acid (VFA) accumulation. However, assays 2, 3, and 4 (with 5.0–10.0% EDP) showed high CH4 yields (mLCH4/gVSadd) of 319, 333, and 317, respectively, demonstrating the feasibility of anaerobic co-digestion of EDP with SDW. In assays 3 and 4, a similar archaeal community structure was observed, dominated by the genera Methanosaeta, Methanolinea, Methanoregula, and Methanobacterium. In assay 2, the archaeal community demonstrated lower dominance due to insufficient substrate adaptation. This study confirms the viability of using EDP in AD systems to generate CH4, suggesting future sustainable applications for this residue. [ABSTRACT FROM AUTHOR]

Denitrification coupled to methane oxidation (DOM) has been shown to be an appropriate process for wastewater treatment applications, since it can reduce greenhouse gas emissions and nitrogen discharges, making wastewater treatment plants more environmentally sustainable. Study of DOM has focused on laboratory-scale application using membrane biological reactors (MBR) or sequency batch reactors (SBR), which have been shown to be able to retain DOM biomass and therefore appropriate for use with this process. However, it is necessary to expand knowledge of the behavior of this process using other configurations, with a view to scaling up. Therefore, in this study, an upflow fixed bed bioreactor (UFBR) was implemented using plastic carriers such as bioballs and Biochips® to carry out the DOM process under anoxic conditions. The reactor reached stable nitrogen removal conditions after approximately 400 days of continuous operation, forming a biomass composed of denitrifying methane-oxidizing microorganisms where the genus Anaerolinea and Methylocystis predominated. Once the biomass was formed and the DOM process was stabilized, maximum nitrite and nitrate removal rates of 17.6 mgN-NO2−/L-d and 8.9 mgN-NO3−/L-d, respectively, and a removal efficiency of methane up to 77% were obtained. This demonstrates the feasibility of the application of the DOM process under anoxic conditions using fixed bed bioreactors, which is promising for further nitrogen removal from wastewater using a varied reactor configuration easily to scaled-up. Highlights: UFBR properly allowed DOM process under anoxic conditions. Biomass formed by DOM microorganisms, heterotrophic denitrifyers and methanotrophs. Up to 90% removal of nitrite and nitrate after 400 days of operation. [ABSTRACT FROM AUTHOR]

Expired, non-edible forms of oats which are considered as trash have the potential to enable biodiesel production at larger scale without competing for any requirements. The process of producing biodiesel has been examined step-by-step, begining with the conversion of oat lipids to FAME. Using DME in a batch reactor, the SCE (super critical carbon dioxide extraction) method was used to extract lipids from oats. The fatty acid profile shows the abundance of C18 compounds from lipid extraction. Catalyst used for the biodiesel production was ZnO–Al2O3; in which varied loadings of copper was carried out. Utilizing XRD, FTIR, N2 sorption, TPD, and SEM examination, the catalyst was characterized. A catalyst with an alcohol ratio of 2:10, a flow rate of 4 ml per hour, 300 mg of oats, and 15% of copper-loaded catalyst was found to be the most effective combination for converting lipids into biodiesel while also exhibiting high selectivity and yield. GCMS spectrum indicates the abundance of C18 fractions at 22.34 min with peak area of 53.69%. The kinetic study such as Arrhenius plot for pure biodiesel and biodiesel blend shows that pure biodiesel at constant temperature shows rate maximum. Engine analysis characteristics such as brake power, torque, BTE, CO, and NO emission data demonstrated the performance of pure biodiesel that was obtained in good yield from oat lipid. [ABSTRACT FROM AUTHOR]

Laccase, the selectively lignin degrader, vital to the initiation of lignocellulosic deconstruction was immobilized onto activated agarose beads to increase its reuse potential. Laccase cross-linked beads (~ 3.42 mm) recorded a specific activity of 23 Umg− 1, retaining about 80.43% enzyme activity after 45 days of storage. The immobilization yield and efficiency were 89% and 97% respectively. The equilibrium data fitted the Freundlich equation (R2 = 0.9987) demonstrating multilayer adsorption and the presence of Cu, Fe, and S in the elemental analysis of immobilized beads established effective binding between activated agarose beads and the laccase protein. Characterization studies of the immobilized laccase-treated crop residues revealed significant differences in the lignin polymer after each treatment cycle. An increase in digestibility of 26.21% and 7.62% was observed in paddy and finger millet-treated straws respectively, over the controls corroborating efficient lignin depolymerization. The propitious performance of laccase beads authenticated in the batch enzymatic reactor to treat crop residues paves headway as a sustainable green technology in the deconstruction of crop residues for use as ruminant feed, augmenting productivity. [ABSTRACT FROM AUTHOR]

The results on zirconia-amine bifunctional modification of hierarchically porous silica monoliths for continuous-flow processes ar presented. The study reports the synthesis and properties of the modified porous monoliths and their performance in the tandem process of deacetalization-Knoevenagel condensation reaction. The properties of the materials were studied by thermal analysis, FTIR spectroscopy, XRF and nitrogen adsorption. It was found that both active centres were uniformly distributed along the monolithic cores, and the antagonistic interaction of the acid and base centres was not observed. It was shown that hydrophobicity of the monolith surface has opposite effects on the efficiency of the studied reactions. The overall rate of the tandem process depends on the rate of the condensation reaction. The performance of the bifunctional microreactors was checked and compared with those of cascade-connected monofunctional microreactors and batch reactor. The yield of cyanocinnamate product obtained in both flow systems was ca. 78%; however, pressure drop in the bimodified reactor was only half of that in the cascade. An effective way of water supply to the reaction system has been proposed. The research demonstrates the benefits of using flow-through structured micro-/mesoreactors in tandem reaction processes. [ABSTRACT FROM AUTHOR]

Changes in the structure and properties of a microbial community of a sequencing batch reactor (SBR) enriched with phosphate-accumulating microorganisms (PAO) after a pH shift to more acidic values (pH 6.7‒7.1) were studied in. The relative abundance of Ca. Accumulibacter decreased from 43.6 to 13.9%, while abundance of potential PAO belonging to the genera Dechloromonas and Thauera increased. The overall share of PAO changed insignificantly (40‒43%). The share of glycogen-accumulating microorganisms (GAO), the main competitors of PAO, remained low throughout the experiment: abundance of the Competibacter 16S rRNA gene fragments before and after the pH shift was 2‒4%. While decrease in pH resulted in a drop in the amount of phosphates released during the anaerobic phase, the amount of phosphorus in the biomass (15‒17%) remained high, as well as phosphorus removal (92‒94%). [ABSTRACT FROM AUTHOR]

H2O2 photosynthesis represents an appealing approach for sustainable and decentralized H2O2 production. Unfortunately, current reactions are mostly carried out in laboratory-scale single-phase batch reactors, which have a limited H2O2 production rate (<100 μmol h−1) and cannot operate in an uninterrupted manner. Herein, we propose continuous H2O2 photosynthesis and extraction in a biphasic fluid system. A superhydrophobic covalent organic framework photocatalyst with perfluoroalkyl functionalization is rationally designed and prepared via the Schiff-base reaction. When applied in a home-built biphasic fluid photo-reactor, the superhydrophobicity of our photocatalyst allows its selective dispersion in the oil phase, while formed H2O2 is spontaneously extracted to the water phase. Through optimizing reaction parameters, we achieve continuous H2O2 photosynthesis and extraction with an unprecedented production rate of up to 968 μmol h−1 and tunable H2O2 concentrations from 2.2 to 38.1 mM. As-obtained H2O2 solution could satisfactorily meet the general demands of household disinfection and wastewater treatments. Photocatalytic H2O2 synthesis is often performed in lab-scale batch reactors with low efficiency. Here, the authors report a biphasic fluid system that enables continuous H2O2 synthesis and automatic product extraction, addressing the limitations of traditional methods. [ABSTRACT FROM AUTHOR]

Pharmaceutically active compounds (PACs) are ubiquitous contaminants that can pollute the environment. This study critically analyzes the sorption of PACs to soil materials based on 137 published papers encompassing 106 PACs and 212 soil materials. The batch technique is commonly employed for sorption studies of PACs to soil, but the experimental setups vary in terms of the type and number of PACs, mixing time, solid to liquid (S/L) ratio, solution type, range of initial concentration, and bio-inhibition method. Sorption competition among PACs or between PACs and dissolved organic matter occurs for certain cases. Linear or close to linear behavior was reported for sorption of many PACs to soil, but sorption of some PACs deviates from linearity. The reaction of PACs to soil is fast at the initial stages but slows down as it approaches equilibrium. PACs characteristics, soil properties, and solution attributes intricately influence the sorption process. Zwitterionic PACs exhibit the highest sorption affinity, whereas neutral PACs display increased sensitivity to soil hydrophobicity. The average sorption coefficient (K) ranges from 0.0915 mL/g for anionic sulfonamides to 84725.5 mL/g for zwitterionic norfloxacin. An increase in the molar volume corresponds to heightened sorption for cationic PACs and reduced sorption for anionic PACs. Increasing solubility, soil organic carbon, cation exchange capacity, S/L ratio, and soil surface area while decreasing pH, ionic strength, and temperature result in an increase in K. The values of K determined by the batch technique are higher than their column-determined counterparts, possibly due to variations in the employed residence times between the two systems. Several models have been developed to estimate K of PACs, but they are limited in their applicability to specific PACs and soil types. Future research related to sorption of PACs to soils has been suggested. [ABSTRACT FROM AUTHOR]

The Pinnick oxidation, due to its tolerance for sensitive functional groups, is widely used in the process of oxidizing α,β-unsaturated aldehydes to corresponding carboxylic acids. The reaction reagents typically include sodium chlorite, buffer salts, and a scavenger. However, the controllability of Pinnick oxidation in the batch reaction process is poor due to the inherent limitations of the reactor's performance. This leads to potential safety risks and necessitates the reaction to proceed slowly under conditions of low temperature and low concentration. In this work, we introduced a new continuous micro-reaction process to intensify the Pinnick oxidation. The water-soluble crotonic acid was selected as a typical object of study. Through the study of reaction parameters and the construction of a micro-reaction system, efficient continuous process was achieved under high-temperature and high-pressure conditions for the first time. Compared to the batch process, the reaction benefited from the superheated condition resulting in a significant acceleration of the reaction rate, efficient gas–liquid interphase mass transfer allowing for effective utilization of the generated chlorine dioxide, and the inherent safety of the microreactor enabling an increase in reaction concentration. In addition, the buffer salts used in the Pinnick oxidation has been successfully replaced by hydrochloric acid and applied to the continuous flow. This work shows the tremendous potential of microreactors in utilizing harsh reaction conditions to achieve process intensification. Article Highlights: A superheated micro-reaction process was introduced into the Pinnick oxidation to achieve efficient and safe preparation of crotonic acid. Efficient gas–liquid interphase mass transfer in microreactor realized effective utilization of the by-product chlorine dioxide. The great replacement of phosphate buffer salts with hydrochloric acid was achieved in continuous flow. [ABSTRACT FROM AUTHOR]

This study investigated the anaerobic co-digestion of sugarcane vinasse (V) and elephant grass silage (S) to produce methane. Box-Behnken experimental design was applied to verify the statistical effects of the elephant grass ensiling time (40, 80 and 120 days), alkaline pretreatment of elephant grass silage (0.5, 2.25 and 4.00% w/v NaOH) and S:V mixture ratio (25:75, 50:50 and 75:25) on the methane yield. The results showed that the ensiling process resulted in the low degradation of lignocellulosic substances, emphasizing the need for pretreatment using more efficient techniques, such as thermo-alkaline, to improve the breakdown of elephant grass fibres. COD removals varied between 35 and 85%, and carbohydrate consumptions ranged from 63 to 72%, with the higher efficiencies for both parameters occurring in the reactors with lower percentages of silage. Cumulative methane yield ranged from 190.77 mLCH4/gVS (in the reactor with S:V of 75:25, 0.50% w/v NaOH and 80 ensiling days) to 1729.80 mLCH4/gVS (in the reactor with S:V of 25:75, 2.25% w/v NaOH and 120 ensiling days). According to ANOVA, S:V ratio was the only variable with a significant effect (p < 0.05) on cumulative methane yield. Therefore, the findings indicate that the relative composition of substrates within the mixture exerted the most significant influence on the process, underscoring the critical role of vinasse as a co-substrate in enhancing methane production despite silage pretreatments. [ABSTRACT FROM AUTHOR]

Metagenome-assembled genomes (MAGs) are microbial genomes reconstructed from metagenomic data and can be assigned to known taxa or lead to uncovering novel ones. MAGs can provide insights into how microbes interact with the environment. Here, we performed genome-resolved metagenomics on sequencing data from four studies using sequencing batch reactors at microcosm (~25 mL) and mesocosm (~4 L) scales inoculated with sludge from full-scale wastewater treatment plants. These studies investigated how microbial communities in such plants respond to two environmental disturbances: the presence of toxic 3-chloroaniline and changes in organic loading rate. We report 839 non-redundant MAGs with at least 50% completeness and 10% contamination (MIMAG medium-quality criteria). From these, 399 are of putative high-quality, while sixty-seven meet the MIMAG high-quality criteria. MAGs in this catalogue represent the microbial communities in sixty-eight laboratory-scale reactors used for the disturbance experiments, and in the full-scale wastewater treatment plant which provided the source sludge. This dataset can aid meta-studies aimed at understanding the responses of microbial communities to disturbances, particularly as ecosystems confront rapid environmental changes. [ABSTRACT FROM AUTHOR]

This work discusses the synthesis of magnetite nanoparticles using microfluidic method. The main characteristics of the resulting nanoparticles were investigated, including chemical composition, size distribution, saturation mass magnetization, and coercive force. To assess the possibility of using nanoparticles for medical and biological purposes, the hemolytic activity of a suspension of magnetite nanoparticles was studied. [ABSTRACT FROM AUTHOR]

Zeolites are crystalline aluminosilicates with open-framework structures and have been widely used in refinery processes. One of the significant utilization processes is cracking heavy feedstocks into lighter fractions, which can be used as a feedstock for subsequent processes such as petrochemical applications. This work aimed to study the effect of the zeolite's different Si/Al ratios on heavy crude cracking under different salt content conditions. The feedstock used for this study is a heavy hydrocarbon fraction contains a large amount of metal and salt. Two synthesized prototype catalysts were prepared and characterized by different physical–chemical methods (SEM–EDX, XRD, N2 physisorption, TPD and TGA). Later the catalysts were mixed with the crudes in a 500 ml autoclave and the catalytic activities were performed in a batch reactor at a temperature of 380–450 °C, 150 rpm, and nitrogen pressure of 10 MPa. The reaction's outlet gases were analysed directly in online Gas Chromatography (GC). The results showed a wide range of impacts on catalyst performance and a noticeable increase in C2 and C3 yield for the desalted crude. Moreover, a higher C3 was produced for both catalysts at 430–450 °C due to the catalyst's large pore. [ABSTRACT FROM AUTHOR]

The microalgae Chlorella sorokiniana was used for the treatment of winery wastewater (WWW). Batch experiments were initially conducted to investigate how biomass acclimatization in different media, dilution of wastewater, and addition of ammonium nitrogen (NH4-N) affect the growth of microalgae and the removal of major pollutants. Afterwards, two sequencing batch reactor (SBR) systems were tested applying different configurations and hydraulic retention times. The biomass collected at the end of the experiments was characterized for proteins, lipids, carbohydrates, amino acid profile, and the existence of lutein, β-carotene, chlorophyll a, and tocopherols. Batch experiments showed that Chlorella sorokiniana acclimatization to urban wastewater enhanced the removal of NH4-N and total phosphorus (TP). The operation of a two-stage SBR system achieved COD and NH4-N removal equal to 85 ± 9% and 91 ± 20%, respectively, while the use of a single-stage system feeding with anaerobically pretreated WWW resulted to COD and NH4-N removal of 78 ± 9% and 95 ± 9%, respectively. Analyses of biomass showed higher protein content (up to 58.8%) in batch experiments with NH4-N addition as well as in SBR experiments. The cultivation of microalgae under SBR conditions enhanced the production of pigments and tocopherols. The maximum concentrations of 1075 mg kg−1, 45.5 mg kg−1, and 131.2 mg kg−1 were achieved for lutein, β-carotene, and tocopherols, respectively, in the one-stage system. Our findings suggested that Chlorella sorokiniana cultivation in WWW not only removed nutrients from WWW but also could potentially serve for the production of value-added ingredients used in food industry, cosmetics, and animal feedstock. [ABSTRACT FROM AUTHOR]

This current study explored the effect of pyrite on the treatment of chlorophenolic compounds (CP) by Fenton process with micron-sized zero-valent iron (ZVI) as the catalyst. The experiments were conducted in batch reactors with 100 mg L−1 CP, 0–0.02 M H2O2, and variable pyrite and ZVI doses (0–1 g L−1). Our findings show that while the reactor with 1 g L−1 ZVI as the only catalyst achieved only 10% CP removal efficiency due to rapid ZVI surface passivation and ZVI particle aggregation, the CP removal efficiency increased with increasing pyrite dose and reached 100% within couple of minutes in reactors with 0.8 g L−1 pyrite and 0.2 g L−1 ZVI. The CP removal was mainly driven by the oxidative treatment of CPs with some strong radicals such as hydroxyl radicals (•OH) while the adsorption onto the catalyst surface was only responsible for 10 to 25% of CP removals, depending on the type of CP studied. The positive impact of pyrite on CP removal by the ZVI/H2O2 system could be attributed to the ability of pyrite to (1) create an acidic environment for optimum Fenton process, (2) provide support material for ZVI to minimize ZVI particle agglomeration, and (3) stimulate iron redox cycling for improved surface site generation. Following oxidative Fenton treatment, the degradation intermediate products of CPs, including some aromatic compounds (benzoquinone, hydroquinone, etc.) and organic acids (e.g., acetic acid), became more biodegradable in comparison to their mother compounds. Overall, the treatment systems with a mixture of ZVI and pyrite as catalyst materials could offer a suitable cost-effective technology for the treatment of wastewater containing biologically non- or low-degradable toxic compounds such as chlorophenols. [ABSTRACT FROM AUTHOR]

Vertical oxidation pond operated in sequencing batch mode (HRT: 1.25 day) with duckweed as the vegetation was used to acclimatize with simulated agricultural wastewater. The maximum removal rate of urea [371 g/(m3.d)] and COD [222.4 g/(m3.d)] were observed at moderate concentrations of urea (500 mg/L), N-P-K (60 mg/L), and pesticide (20 mg/L). Inhibition and toxicity posed by higher concentrations, decreased the removals of urea (83% to 61%), COD (81% to 51%), and TDS (76% to 50%) at the end of the acclimatization. Steady removal (> 99%) of PO43−-P was observed during acclimatization. Effluent pH increased due to the generation of NH4+-N (maximum 370 ± 5 mg/L) from the assimilation of urea. Oxidation of ammonia led to the maximum generation of NO2−-N and NO3−-N of 10 mg/L and 9 mg/L, respectively. Particles less than 300 μm increased, and both specific gravity (from 2.62 to 2.42) and maximum dry density (from 1.73 to 1.30 g/cm3) of the base soil decreased with an increase in urea, N-P-K, and pesticide. Reactor biomass increased (1.42 to 1.90 g/L) up to initial concentrations of urea (500 mg/L), N-P-K (60 mg/L), and pesticide (20 mg/L), then decreased (1.68 g/L) with an increase in concentration. [ABSTRACT FROM AUTHOR]

The simulations and predictions obtained from mathematical models of bioprocesses conducted by microorganisms are not overvalued. Mechanistic models are bringing a better process understanding and the possibility of simulating unmeasurable variables. The Dynamic Energy Budget (DEB) model is an energy balance that can be formulated for any living organism and can be classified as a structured model. In this study, the DEB model was used to describe E. coli growth in a batch reactor in carbon and nitrogen substrate limitation conditions. The DEB model provides a possibility to follow the changes in the microbes' cells including their elemental composition and content of some important cell ingredients in different growth phases in substrate limitation conditions which makes it more informative compared to Monod's model. The model can be used as an optimal choice between Monod-like models and flux-based approaches. Key points: • The DEB model can be used to catch changes in elemental composition of E. coli • Bacteria batch culture growth phases can be explained by the DEB model • The DEB model is more informative compared to Monod's based models [ABSTRACT FROM AUTHOR]

Textile effluent discharge can negatively impact the environment and living organisms due to its potential toxicity, higher percentages of total organic carbon (TOC) contents, and so on. The study investigates the extraordinary performance of the electrocoagulation process (ECP) combined with powdered activated carbon (PAC) as a highly effective and environmental friendly method of treating textile effluents. This scientific work mainly includes the focus on removing toxic components in textile effluents, such as high concentrations of colour and TOC using synthesized PAC derived from coconut shells coupled with the ECP (ECP–PAC). Initially, PAC was characterized by using XRD, Raman, BET, FTIR, and TGA studies. Subsequently, the pilot-scale ECP–PAC batch reactor was constructed with iron (Fe) as an anode and copper (Cu) as a cathode. The pilot-scale ECP–PAC batch reactor has achieved higher treatment efficiency in a shorter reaction time with low energy consumption compared to a stand-alone ECP. Further, the optimum conditions for effective ECP–PAC have been optimized, such as pH 7.5, applied current density (0–50 mA/cm2), reaction time (0–30 min), electrode combinations (Fe-Cu) with electrode distances of 5 cm apart, and an optimum dose of 5 g/L of PAC. Specifically, 98% of the colour and 96% of the TOC contents present in the industrial textile effluent were treated in 15 and 30 min, respectively. In quantitative perspectives, the developed batch reactor has sharply decreased TOC (324.1 mg/L), IC (1410 mg/L) and TC (1019 mg/L) to 13.55 mg/L (96%), 31.49 mg/L (97%), and 48.05 mg/L (95%), respectively, in 30 min demonstrating its sensitivity and selectivity with the utmost care. Moreover, the physicochemical properties of the treated water were convincingly assessed. That is, it remains suitable for the seed germination of mung bean and chlorophyll content study. Thus, the developed methodology could effectively reduce freshwater consumption in the agricultural sector, increase freshwater availability in water-scarce regions, and facilitate the increase of the recharging capacity of groundwater tables. [ABSTRACT FROM AUTHOR]

This study investigates the design of a serpentine continuous photocatalytic reactor for the degradation of methylene blue (MB) dye as a model contaminant of the synthetic textile wastewater under sunlight irradiation using supported zinc oxide nanorods (ZnO NRs) catalyst. ZnO NRs were fabricated on glass substrates using the microwave-assisted hydrothermal method and characterized by different techniques. The characterized results show that wurtzite crystal structure ZnO NRs has native defects in the visible region. Water contact angle measurement shows the highest wettability of ZnO NRs surface at pH 8. Photocatalytic degradation was conducted with MB dye under sunlight in a batch system followed by a continuous flow reactor. In the batch reactor, three different concentrations of 10, 50, and 100 ppm MB were examined under sunlight. MB degradation reached 100%, 83%, and 62% under sunlight for 10, 50, and 100 ppm, respectively, after 3 h of irradiation. In the continuous flow reactor, 100 ppm MB was degraded 80%, 67%, 58%, and 46% at flow rates of 1.5, 2.5, 4.5, and 6.0 ml/min, respectively. The photocatalytic degradation of MB dye follows pseudo-first-order with the highest absorption rate constant of about 0.0066 h-1 obtained for 1.5 ml/min flow rate. Furthermore, a multi-step process using a continuous flow reactor achieved ~ 90% MB degradation after five repeated steps. Moreover, the reusability of ZnO NRs catalysts was conducted for five repeated cycles using two different cleaning methods of used ZnO NRs, whereby the photo cyclic cleaning process achieved 71%, and the regular cleaning process attained only 45% degradation. [ABSTRACT FROM AUTHOR]

Reaction mechanism involved in mostly general titanium metallurgy books and literature differs from some basics and is difficult to be understood for researchers and engineers. Although various authors have proposed different types of theories to recognize this reduction process, there is still no consensus on the reaction pathways and kinetic characteristics of magnesiothermic reduction of TiCl4 in the semi-batch reactor, and the theoretical innovations are required for further research of today's titanium sponge metallurgy. To develop a better understanding of the reduction mechanism of magnesiothermic reduction of TiCl4 in a semi-batch reactor, the present study defined a minimum set of independent reactions via generalized stoichiometry methodology, and proposed an innovative kinetic modeling approach via the net chemical reaction rate models of the main components and the reaction rate models of the independent reactions near the gas–liquid interfaces of magnesiothermic reduction of TiCl4. We also established the overall chemical reaction kinetics model of magnesiothermic reduction of TiCl4via the isothermal reduction experiment in a prototype 12 tons Kroll reactor. [ABSTRACT FROM AUTHOR]

Domestic wastewater source-separated treatment has attracted wide attention due to the efficiency improvement of sewage treatment systems, energy saving, resource reuse, and the construction and operation cost saving of pipeline networks. Nonetheless, the excess source-separated urine still demands further harmless treatment. Sequencing batch biofilm reactor (SBBR), a new type of composite biofilm reactor developed by filling different fillers into the sequential batch reactor (SBR) reactor, has higher pollutant removal performance and simpler operation and maintenance. However, the phosphorus removal ability of the SBBR filling with conventional fillers is still limited and needs further improvement. In this study, we developed two new fillers, the self-fabricated filler A and B (SFA/SFB), and compared their source-separated urine treatment performance. Long-term treatment experimental results demonstrated that the SBBR systems with different fillers had good removal performance on the COD and TN in the influent, and the removal rate increased with the increasing HRT. However, only the SBBR system with the SFA showed excellent PO43−-P and TP removal performance, with the removal rates being 83.7 ± 11.9% and 77.3 ± 13.7% when the HRT was 1 d. Microbial community analysis results indicated that no special bacteria with strong phosphorus removal ability were present on the surface of the SFA. Adsorption experimental results suggested that the SFA had better adsorption performance for phosphorus than the SFB, but it could not always have stronger phosphorus adsorption and removal performance during long-term operation due to the adsorption saturation. Through a series of characterizations such as SEM, XRD, and BET, it was found that the SFA had a looser structure due to the use of different binder and production processes, and the magnesium in the SFA gradually released and reacted with PO43− and NH4+ in the source-separated urine to form dittmarite and struvite, thus achieving efficient phosphorus removal. This study provides a feasible manner for the efficient treatment of source-separated urine using the SBBR system with self-fabricated fillers. [ABSTRACT FROM AUTHOR]

The objective of this research is to investigate the effect of palladium insertion into zirconium(IV)-based Metal-Organic Frameworks (MOFs) containing a benzene 1,3,5-benzenetricarboxylate organic linker [Pd/Zr6O4(OH)4(O2C2H3)6(BTC)2] or (Pd/Zr-BTC) on its structure and its ability to catalyze the hydrogenation process of citronellal. Zr-BTC was synthesized by a modulated-solvothermal method at 135 °C. Post-synthesis modification with Pd nanoparticle was conducted using the wet impregnation method with a concentration of 2.5% (w/w). Powder XRD analysis showed that the presence of Pd was identified by a new peak at 2θ = 40.0° and the decrease of Zr-BTC crystallinity. The presence of Pd also increases the irregularity of Zr-BTC morphology and contains an average particle size up to 16.58 ± 6.4 nm according to SEM and TEM analysis. Modification with Pd lead to a decrease in surface area, pore volume, and diameter of Zr-BTC up to 1095 m2/g, 0.15 cc/g, and 18.6 Å, respectively. Moreover, the addition of Pd does not affect the thermal stability of Zr-BTC. An examination of the hydrogenation of citronellal was carried out using two distinct setups. The first involved conducting reactions in a batch reactor system at a temperature of 80 °C and under a hydrogen pressure of 10 bar for a duration of 6 h. The second approach entailed performing reactions in a hydrogen-filled balloon under atmospheric pressure (1 atm) at 80 °C for a period of 6 h. The addition of Pd into Zr-BTC increases its activity up to 83.2%, and selectivity (up to 53.7%) in citronellal hydrogenation for both batch and balloon systems. Interestingly, the employment of batch reactors is found to be more effective. [ABSTRACT FROM AUTHOR]

Pharmaceutical industry is challenged by the rising development costs, strict regulatory and environmental requirements all while racing to deliver complex molecules to market. The need to be the first-in-class brings about shorter lifetime to the launched products in favor of better functioning followers. In addition, a shift from large volume blockbusters towards small volume production of complex molecules presents a unique opportunity to challenge the status quo in pharmaceutical manufacturing. Traditional batch manufacturing, while foundational, presents hurdles in scaling and efficiency, particularly for demanding reactions. Continuous manufacturing has emerged as a promising alternative, delivering better control and uniformity of operating conditions, mirroring the efficiencies found in small-scale batch reactors. However, continuous manufacturing is not universally applicable. As a solution, a combination of the two into hybrid manufacturing processes, appears to fill this gap effectively. While the concept of hybrid manufacturing is not new, the current perspective adds an additional angle to the integration of both technologies. Authors propose to sustain the continuity of the operation for batch mode processes by decreasing the reactor size and increasing the level of automation. Furthermore, modular fabrication of smaller-footprint technological platforms is expected to synergize other advancements in the field, such as digitalization, automation, and standardization. As a result, a leap towards the implementation of advanced manufacturing to drive sustainability in pharmaceutical industry is more tangible than ever. [ABSTRACT FROM AUTHOR]

To understand and predict the effect of mixing in a mixer or reactor, characterization is essential. The Villermaux-Dushman system of competitive parallel reactions is one of the most frequently used methods to obtain details on the micromixing behavior in mixers and reactors. For quantitative information, a model can convert experimental data into a universal micromixing time, which can be used to compare set-ups and reaction conditions. Different modeling approaches have been developed over time and complicate the comparison of results with newfound micromixing times. In this work, these different modeling approaches are elaborated upon to show the significant differences that can arise between these models. Special attention goes out to a model for continuous-flow mixers, which operates differently and has different characteristics compared to mixing in conventional batch reactors. The volume fractions of the two phases being mixed are generally closer to one another in flow mixers, requiring adaptations in the experimental and modeling approach. Several models were tested, after which the interaction by exchange with the mean (IEM) model was selected. Using this model, micromixing times were determined for a variety of continuous-flow mixers under different operating conditions. [ABSTRACT FROM AUTHOR]

Photochemistry and continuous flow chemistry are synthetic technology platforms that have witnessed an increasing uptake by chemical industries interested in complex organic molecule synthesis. Simultaneously, automation and data science are prominent targets in organic synthesis and in chemical industries for streamlined workflows, meaning hardware-software interaction between operators and devices is crucial. Since undergraduate teaching labs at public-funded research Universities typically (i) lack budget for commercial, user-friendly continuous flow reactors and (ii) do not teach synthetic chemists how to program or interact with reactors, there is a disparity between the skills undergraduates are equipped with and the skills that future industries need. We report a teaching lab project where undergraduates assemble, program and execute a continuous flow photoreactor to realize a multigram-scale photoredox catalyzed oxidation reaction. A palladium-free synthetic access to the starting material was described to further cut costs. Not only does this exercise introduce useful skills in reactor design, programming and wet chemistry (both photochemical and thermal, both batch and flow), it also accommodates both the typical budget and afternoon timeslot (2-3 h) of a teaching lab and can be followed by thin-layer chromatography/color changes without necessarily requiring access to NMR facilities. [ABSTRACT FROM AUTHOR]

Recently demonstrated as a novel reaction screening technology, the stop-flow micro-tubing (SFMT) reactors amalgamate features from continuous micro-flow and conventional batch reactors, resulting in a more logical and rigorous synthesis approach. When compared to traditional batch reactors, SFMT provides a safer and more efficient alternative, particularly suitable for chemical reactions under drastic conditions. The incorporation of commercially available transparent micro-tubing into SFMT makes it an excellent choice for light-mediated reactions, ensuring more uniform exposure to light. And SFMT stands apart from continuous-flow reactors by offering a notably convenient screening approach that is unrestricted by residence time and reactor size, while also effectively eradicating the risk of cross-contamination. The successful reactions developed within the SFMT reactor can be easily translated to continuous-flow synthesis for large-scale production. Overall, the SFMT reactor system exhibits similarities to continuous-flow reactors while surpassing batch reactors, especially for reactions involving gas reagents and/or requiring light illumination. This review aims to provide a comprehensive survey of the synthetic application of SFMT. [ABSTRACT FROM AUTHOR]

In a continuous flow microreactor system, a continuous nitration process of 2-(2,4-dichloro-5-nitrophenyl)-4-(difluoromethyl)-5-methyl-1,2,4-triazol-3-one which is the key intermediate for the synthesis of important triazolinone herbicide Sulfentrazone was developed. The effects of molar ratio of mixed acids, molar ratio of nitric acid to substrate, reaction temperature, total flow rate and residence time in the microreactor on nitration reaction were studied. The results showed that when the flow rate of the material was 60 mL/min, the molar ratio of nitrate to sulfur mixed acid was 1:6, the molar ratio of nitric acid to raw material was 1.1:1, the reaction temperature was 60 ℃, and the residence time was 30 s, the product can be obtained in 97% yield. Compared with the results of nitration process using traditional batch reactors, the use of continuous flow microreactors improved reaction efficiency and achieved higher yields. A characterization kinetics study was conducted on this reaction, and the pre-exponential-factor and activation energy for 2-(2,4-dichlorophenyl)-4-(difluoromethyl)-5-methyl-1,2,4-triazol-3-one nitration were obtained. The activation energy of the reaction is 40.204 kJ/mol. The continuous flow microreactor system greatly increased liquid-liquid two phases mass transfer efficiency, while accurately controlling the reaction temperature and residence time in the reactor. [ABSTRACT FROM AUTHOR]

In this era of industrial revolution and diminishing petroleum reserves, alternative options (woody biomass) for building next-generation fuels need to be critically explored. Here, process engineering aspects of 5-hydroxymethylfurfural (5-HMF) from Bambusa bamboo in ionic liquid ([Bmim]Cl) in the presence of a catalyst, CrCl3, in batch reactor have been explored in great detail. 5-HMF upon hydrogenation liberates 2,5-dimethylfuran (DMF), which is a liquid fuel. To maximize the production of platform chemical-5-HMF, effects of different mixing speeds (150–1200 rpm) and temperatures (120–160 °C) were captured on the yield of 5-HMF and glucose. A highest 5-HMF yield (25%) was obtained at 120 °C and 1200 rpm within a reaction time of 6 h. Moreover, a kinetic analysis of transformation of biomass into 5-HMF was carried out using curve fitting to estimate kinetic constants k1, k2, and k3. Mixing at asymptotic limits, i.e., no mixing (0 rpm) and very high mixing (1200 rpm), enables us to devise mixing regimes: 0–400 rpm, mass transfer–limited regime; 400–1100 rpm, intermediate regime; and > 1100 rpm, reaction-limited regime. Thus, tremendous improvement in reaction rate constants (k1, k2, k3) was observed when operated at higher mixing conditions (reaction-limited regime). Mixing limitation for this IL-based system can be eliminated by operating the reactor above 800 rpm, whereas lower temperature restricts conversion of 5-HMF to LA and FA. Hence, higher mixing speeds, i.e., > 1100 rpm, and lower temperature, i.e., ≈ 120 °C, can be suggested as the optimum operating conditions for maximization of platform chemical-5-HMF in the catalytic conversion of Bambusa bamboo in batch reactor. [ABSTRACT FROM AUTHOR]

The energy cost and harmful effect of residual chlorine produced as a by-product in the electrochemical processes are the main obstacles in the extensive use of electrochemical recirculating aquaculture systems (ERAS). In this study, a pilot electrochemical system was used in a shrimp cultivation experiment to investigate the effects of current density, geometric feature, timing, and other parameters on the effective control of inorganic nitrogen, pathogens, and residual chlorine in aquaculture water. A 50-L electrochemical batch reactor (BR) equipped with Ti-RuO2/Ti electrodes could effectively remove inorganic nitrogen (the initial concentration was 4.0 mg/L) and inactivate Vibrio in the aquaculture seawater in 5 min, when a current density of 66 mA/cm2 and electrodes with a surface area of 154 cm2 were used. Air stripping was found to be effective in resolving residual chlorine produced from electrochemical process. In the experiment of shrimp cultivation, the ERAS equipped with a 50-L batch reactor and 500-L shrimp tank effectively kept the inorganic nitrogen concentration in the rearing water to a desirable concentration (0.2 mg/L) when a nitrogen load of 4.3 g (transformed from a daily quota of commercial prawn feeds) was used. By precisely controlling the time at which electrooxidation and air stripping alternated, an electrochemical recirculating aquaculture system could effectively remove inorganic nitrogen and residual chlorine, carry out disinfection, and reduce energy cost. [ABSTRACT FROM AUTHOR]

Hyperbranched polymer–supported ruthenium NPs were used for hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) in water. The catalytic nanocomposite showed 99.9% LA conversion and 100% GVL selectivity under mild conditions and low Ru loading in batch reactor under H2. Ru NPs formed in situ during the hydrogenation of LA demonstrated the higher catalytic activity over pre-synthesized Ru NPs. Superior catalytic properties of Ru nanocomposites are attributed both to the formation of small Ru NPs and to the effect of pyridine containing polymer support, which provides a reliable dispersion of Ru species over support and at the same time due to weak alkalinity, promotes interaction with LA thereby facilitating catalytic reaction. The functional hyperbranched polymer contributes to high stability of supported Ru NPs which was demonstrated in six consecutive catalytic cycles. TEM, XPS, EDS, XRD were used to analyze the structure, NPs distribution, and oxidation state of Ru catalysts before and after catalytic reactions. [ABSTRACT FROM AUTHOR]

In order to develop a promising means of achieving mainstream short-cut nitrification, this study evaluated the effect of thermal shock on nitrite accumulation using intermittent offline and continuous inline heat treatment of biomass in sequencing batch reactors (SBRs). The SBRs fed with municipal wastewater were operated at a solid retention time of 7 days and nitrogen loading rate of 0.04 gN/L·d to 0.08 gN/L·d without the application of pre-treatment. Contrary to literature studies that showed suppression of nitrite-oxidizing bacteria at temperature 60 to 80 °C, nitrite accumulation was achieved temporarily when 20% of the biomass was heated for 2 h at 47 °C, as well as in continuously heated SBRs at 37 °C and 42 °C. The continuously heated reactors at 37 °C and 42 °C produced a maximum nitrite accumulation ratio (NAR) of 0.59 and 0.79, respectively, whereas the intermittent offline heating at 47 °C-2 h produced a NAR of 0.37. Although nitrite accumulation was stable only for 10–12 days in all heated reactors, this study demonstrates the achievement of mainstream partial nitrification (PN) at lower temperature (42 °C) than that reported in literature and also highlights the potential for achieving PN by implementing heat treatment of a portion of the return activated sludge (RAS) in biological nitrogen removal (BNR) systems. During the time when full nitrification was achieved, Nitrospira was more dominant than Nitrosomonas in all reactors at ratios of 1.4:1, 2.4:1, 2.4:1, and 3.7:1 for the control SBR (22 °C), 47 °C -2 h offline heating SBR, 37 °C SBR, and 42 °C SBR, respectively, suggesting that it may have played a role as a comammox bacteria capable of degrading ammonia to nitrates at elevated temperature. [ABSTRACT FROM AUTHOR]

Due to the slow growth rate of anammox bacteria, enriched sludge is required for the rapid start-up of anammox-based reactors. However, it is still unclear if long-term stored anammox sludge (SAS) is an effective source of inoculum to accelerate reactor start-up. This study explored the reactivation of long-term SAS and developed an efficient protocol to reduce the start-up period of an anammox reactor. Although stored for 13 months, a low level of the specific anammox activity of 28 mg N/g VSS/d was still detected. Experimental Phase 1 involved the direct application of SAS to an upflow sludge bed reactor (USB) operated for 90 d under varying conditions of hydraulic retention time and nitrogen concentrations. In Phase 2, batch runs were executed prior to the continuous operation of the USB reactor. The biomass reactivation in the continuous flow reactor was unsuccessful. However, the SAS was effectively reactivated through a combination of batch runs and continuous flow feed. Within 75 days, the anammox process achieved a stable rate of nitrogen removal of 1.3 g N/L/day and a high nitrogen removal efficiency of 84.1 ± 0.2%. Anammox bacteria (Ca. Brocadia) abundance was 37.8% after reactivation. These overall results indicate that SAS is a feasible seed sludge for faster start-up of high-rate mainstream anammox reactors. [ABSTRACT FROM AUTHOR]

This work represents reductive amination of 5-hydroxymethyl-2-furaldehyde (HMF) to 5-hydroxymethyl-2-furfurylamine (HMFA) catalyzed by Ni-based bimetallic catalysts. It was found that hydroxyapatite (HAP) was the excellent support for the reaction and the bimetallic 3 wt%Ni–2 wt% Co-loaded HAP (Ni3Co2HAP) catalyst gave the highest activity of 60% at 2 mmol scale by a batch reactor. X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM) results suggested that the large metallic composition of both Ni and Co were the crucial factor for high activity on the CoNi-supported HAP catalyst for the synthesis of HMFA via reductive amination of HMF. [ABSTRACT FROM AUTHOR]

The kinetics of methane decomposition in low frequency (60 Hz) AC arc plasmas was investigated using on-line mass spectrometry and optical emission spectroscopy (OES) in a batch reactor configuration at pressures up to 3 bar absolute. Plasma conversion of CH4 results largely from thermal dissociation and was seen to follow first-order kinetics up to high conversions (> 90%) without observing any rate impedance from reverse hydrocracking. H– and C-atom selectivities for H2, C2H2, and C2H4 were 78% (1.56 mol H2/mol CH4 reacted), 36% (0.18 mol C2H2/mol CH4), and 30% (0.15 mol C2H4/mol CH4), respectively, at 3 bar. In other experiments, H2 diluent concentration played an important role in CH4 dissociation and final product distributions; H abstraction reactions increased the rate of CH4 decomposition at low H2 (yH2 < 0.6) while high H2 (yH2 > 0.6) impeded CH4 decomposition due to hydrocracking of C2 products. The rate of CH4 dissociation was seen to increase with pressure, up to 0.11 mol/m3/s, and the specific energy requirement (SER) decreased with pressure to 365 kJ/mol CH4 at 3 bar. The latter suggests that even higher operating pressures may improve the efficiency of plasma conversion of CH4, and ultimately that plasma pyrolysis may be a viable and energy efficient route to clean (turquoise) H2 and further implementation of chemical process electrification. [ABSTRACT FROM AUTHOR]

A lab-scale granular sludge sequencing batch reactor (G-SBR) system was operated using synthetic wastewater. The total nitrogen removal efficiency of 85% was obtained together with the achievement of complete total phosphorus removal with average granule diameter of 400 µm. Dual-step nitrification and denitrification model with fixed biofilm thickness was used for performance analysis. The denitrification mode only contributed to TN removal with 25% which can be calculated with process stoichiometry. The remaining nitrogen removal could be explained by simulating simultaneous nitrification and denitrification which was responsible for 75% denitrification during aerobic period. In addition, low NO3− concentration at the beginning of the fill period provided advantage for securing a prolonged anaerobic period for enhanced biological phosphorus removal (EBPR). The model parameters of boundary layer thickness (zBL = 50 µm) and half-saturation of O2 for nitrite-oxidizing bacteria (KO2,NOB = 0.5 gO2/m3) were tuned to fit NO2 and NO3 profiles in SBR cycle. [ABSTRACT FROM AUTHOR]

Chromium [Cr] contamination in groundwater is one of the serious environmental concerns due to the carcinogenicity of its water-soluble and mobile hexavalent [Cr(VI)] form. In spite of the existence of multiple precipitation and adsorption-based Cr(VI) remediation technologies, the usage of sulfidated nano zerovalent iron (S-nZVI) has recently attracted researchers due to its high selectivity. Although S-nZVI effectively immobilized Cr(VI), its long-term performance in multiple shifted equilibrium has not been explored. In this contribution, influences of S-nZVI dosage, initial concentration of Cr(VI), pH, ionic strength, total hardness, sulfate, carbonate, and silicate were probed in ultrapure water. Further experiments were performed in synthetic groundwater to investigate the effects of initial concentration of Cr(VI) in the pH range of 4–8 for 1 g L−1 S-nZVI dosage. Cr(VI) removal rate was quantified in groundwater without pH fixation. Finally, a comparative study between conventional nano zerovalent iron (nZVI) and S-nZVI was conducted in sequential batch reactors to investigate their respective efficiencies during repeated usage. Mechanistic interpretation of the processes governing the immobilization of Cr(VI) was done by integrating the results of these experiments with the metadata. While aggregation due to magnetic properties and rapid oxidation of Fe decreased the efficiency of nZVI with repeated usage, sulfidation minimized the passivation and favored an extended reducing environment because of continuous electron transfer from iron and sulfur components. [ABSTRACT FROM AUTHOR]

During long-term cultivation in a laboratory sequencing batch reactor in the phosphorus removal mode, granule-like aggregates of two morphotypes, differing in their physical structure and microbial composition, with predominance of different microbial physiological groups, were formed out of the activated sludge floccules. Phosphate-accumulating bacteria Candidatus "Accumulibacter" prevailed in one morphotype, and glycogen-accumulating bacteria Candidatus "Competibacter," in the other. These are aerobic microorganisms, known to compete for the substrate during the anaerobic period of the anaerobic/aerobic cultivation cycle. Aggregate formation paralleled development of phosphate-accumulating microorganisms, increase in their relative abundance, and higher phosphorus removal efficiency. [ABSTRACT FROM AUTHOR]

The proliferation of water hyacinths is a global issue with significant environmental and social implications, and its proper management is a critical issue. Anaerobic digestion (AD) of compressed water hyacinth juice (WHJ) is key to efficiently utilizing water hyacinth biomass, but a simpler and more cost-effective method has yet to be established. In this study, the effectiveness of biochar carriers derived from local waste biomass (i.e., coffee husk) for WHJ treatment was evaluated in a sequential batch reactor. This was compared to conventional AD carriers (polyurethane sponge) and no-carrier conditions. The no-carrier condition resulted in process failure after 40 days due to the accumulation of volatile fatty acids from the substrate overload. In contrast, the biochar condition showed a significant CH4 yield (472 mL/g-VS) and total organic carbon removal (88.6%), comparable to the sponge carrier condition. Scanning electron microscope observation revealed an aggregation of mainly rod-shaped microorganisms in the biochar pores, indicating biofilm formation and a rise in microbial concentration. Nano-archaea (Candidatus Diapherotrites archaeon ADub.Bin253), which have a symbiotic relationship with methanogens, were detected, particularly in carrier-filled conditions, with a relative archaea abundance of 12.9–28.6%. This study highlights the effectiveness of using coffee husks to treat WHJ, which can both exist in the same region, and suggests an alternative way of using locally generated biomass for local waste treatment. [ABSTRACT FROM AUTHOR]

The catalytic transesterification of vegetable oil over heterogeneous catalysts is an effective approach for biodiesel production. To elucidate the role of MgO in catalyzing this reaction, several CaO-MgO catalysts with various Mg/Ca ratios were synthesized by co-precipitation. The catalysts were characterized by BET, XRD, SEM, HRTEM, FTIR, TGA, CO2-TPD, O2-TPO, and in situ DRIFTS. The catalytic performance in the transesterification of soybean oil with methanol was evaluated in a stirred batch reactor. The results indicated that the synthesized pure MgO had weak basic sites and poor pore structure, showing the lowest activity. The added Mg in the CaO-MgO composites was present in both doped and supported forms. The doped Mg reduced the lattice spacing of CaO, improved the intensity and number of basic sites, and enhanced the activity of catalysts, while the supported Mg hindered the diffusion of reactants to the basic sites. The amount of the doped Mg showed a maximum value due to the solubility nature of CaCO3 and MgCO3. 1Mg3Ca (Mg/Ca=1/3) exhibited the highest activity with a biodiesel yield of 92.28% at 60 °C for 2 h. CaO is sensitive to water and CO2, forming hydroxides and carbonates. The supported MgO with a low porous structure well protected the basic sites from contamination. High-temperature treatment is an effective method to remove the contaminates and the removal temperature increases in the order of H2O < Mg(OH)2 < Ca(OH)2 < CaCO3. [ABSTRACT FROM AUTHOR]

The present study was performed to compare the chemical oxygen demand (COD) removal performances of conventional Fenton (c-Fenton) and photo-Fenton (p-Fenton) processes from real laundry wastewater in batch reactors. The effects of pH, Fe2+ dose, H2O2 dose, and H2O2/Fe2+ ratio on both Fenton processes were investigated. The maximum removal was found at pH 3 for both Fenton processes. The optimum H2O2/Fe2+ ratio was determined to be 900/400 for the c-Fenton process and 600/400 for the p-Fenton process. The COD removal efficiencies in the optimum H2O2/Fe2+ ratios were achieved as 90 and 99% for c-Fenton and p-Fenton processes, respectively. Kinetic models were tested to understand the oxidation mechanism using Behnajady–Modirshahla–Ghanbery (BMG), zero-order, first-order, and second-order reactions kinetics. The results indicated that the experimental data were described well by BMG model (R2 = 0.988) for c-Fenton, and the zero-order kinetic model (R2 = 0.976) for p-Fenton process. The results supported the use of p-Fenton due to achieved faster oxidation with fewer reagents to remove COD from the wastewater. [ABSTRACT FROM AUTHOR]

The present study was performed to compare the chemical oxygen demand (COD) removal performances of conventional Fenton (c-Fenton) and photo-Fenton (p-Fenton) processes from real laundry wastewater in batch reactors. The effects of pH, Fe2+ dose, H2O2 dose, and H2O2/Fe2+ ratio on both Fenton processes were investigated. The maximum removal was found at pH 3 for both Fenton processes. The optimum H2O2/Fe2+ ratio was determined to be 900/400 for the c-Fenton process and 600/400 for the p-Fenton process. The COD removal efficiencies in the optimum H2O2/Fe2+ ratios were achieved as 90 and 99% for c-Fenton and p-Fenton processes, respectively. Kinetic models were tested to understand the oxidation mechanism using Behnajady–Modirshahla–Ghanbery (BMG), zero-order, first-order, and second-order reactions kinetics. The results indicated that the experimental data were described well by BMG model (R2 = 0.988) for c-Fenton, and the zero-order kinetic model (R2 = 0.976) for p-Fenton process. The results supported the use of p-Fenton due to achieved faster oxidation with fewer reagents to remove COD from the wastewater. [ABSTRACT FROM AUTHOR]

This research assessed the effect of decoupling hydraulic retention time (HRT) and solid retention time (SRT) on the production of volatile fatty acids (VFAs) via anaerobic fermentation of beet molasses. The performance of a continuous stirred tank reactor (CSTR, STR = HTR = 30 days) and two anaerobic sequencing batch reactors (AnSBR) with decoupled STR (30 days) and HRT (20 and 10 days) was compared. Previously, a temperature study in batch reactors (25, 35, and 55 °C) revealed 25 °C as the optimal temperature to maximize the VFAs yield and the long-chain VFAs (> C4) production, being selected for the continuous reactors operation. An HRT of 20 days in AnSBR led to an enhancement in bioconversion efficiency into VFAs (55.5% chemical oxygen demand basis) compared to the CSTR (34.9%). In contrast, the CSTR allowed the production of valuable caproic acid (25.4% vs 4.1% w/w of total VFAs in AnSBR). Decreasing further the HRT to 10 days in AnSBR was detrimental in terms of bioconversion efficiency (21.7%) due to primary intermediates (lactate) accumulation. By decoupling HRT and SRT, VFAs were maximized, revealing HRT as an effective tool to drive specific conversion routes (butyrate- or lactate-fermentation). [ABSTRACT FROM AUTHOR]

Kinetic assays with a nitrifying consortium with whole nitrifying cells amended with 5 mg 2-CP-C/L and 100, 200, 300, or 500 mg NH4+–N/L were carried out in batch and nitrifying sequencing batch reactor (SBR) cultures. No nitrification activity was observed in batch assays with 100 mg NH4+–N/L and 5 mg 2-CP-C/L. Nevertheless, increasing the ammonium concentration from 200 to 500 mg NH4+–N/L allowed simultaneous ammonium and nitrite oxidation even in the presence of 5 mg 2-CP-C/L plus the halogenated compound consumption. Under these conditions, the ammonium monooxygenase enzyme participated in 2-CP consumption. Complete nitrification and simultaneous elimination of 5 mg 2-CP-C/L were achieved in the SBR amended with 200–500 mg NH4+–N/L. The inhibitory effect of 2-CP on the nitrite oxidation process completely disappeared under these conditions. Assays with nitrifying cell-free extracts, ammonium (100 mg NH4+–N/L), and 2-CP (5 mg 2-CP-C/L) were also conducted. In the absence of 2-CP, the nitrifying cell-free extracts maintained up to 60% of the nitrifying activity compared to whole-cells. Contrary to whole-cell assays, cell-free extracts were capable of simultaneously oxidizing ammonium and consuming 2-CP. However, the inhibitory effect of 2-CP on nitrification was still present as lower specific rates of ammonium consumption and nitrate production were obtained. Thus, these assays indicate that the presence of 2-CP affects both, the ammonium transport mechanism and the activity of nitrifying enzymes. [ABSTRACT FROM AUTHOR]

The effective treatment of phenol has become one of the most intractable issues in the field of air and water pollution. Herein, the visible-light photocatalysis degradation of phenol under a continuous plug flow reactor (PFR) system was investigated. For this purpose, graphitic carbon nitride (g-C3N4) nanosheets having a high nitrogen content were prepared using an NH4Cl-induced low-temperature method. The structural characteristics of the prepared g-C3N4 and nitrogen-rich g-C3N4 nanosheets were characterized using XRD, FE-SEM, TEM, BET, and UV–Vis DRS. The reactor performance of the prepared g-C3N4 and nitrogen-rich g-C3N4 nanosheets was evaluated using different phenol concentrations and flow rates. The nitrogen-rich g-C3N4 nanosheets showed effective phenol degradation, with an efficiency of approximately 99% after continuous operation for 5 h, which was significantly better than bulk g-C3N4, which gave a degradation efficiency of 40% in 5 h, owing to the larger surface area and more active sites. Only 20% of the phenol in the batch reactor degraded over the course of 180 min under visible light in the presence of bulk g-CN, as opposed to about 85% for g-CNNs. To better understand the reaction process, a degradation mechanism was proposed along with the study of recycling photocatalytic systems that show the stability of the catalyst. The results obtained have effectively demonstrated that the continuous plug flow photocatalytic reactor built of nitrogen-rich g-C3N4 nanosheets could be offered as an effective and potential technique for treating wastewater. [ABSTRACT FROM AUTHOR]

FG-06 is a microbial consortium screened from activated sludge of coking wastewater treatment plant, which has excellent heterotrophic nitrification-aerobic denitrification ability. The aim of the study is to evaluate the possible factors affecting its heterotrophic nitrification performance and the feasibility of its application in the treatment of coking wastewater in a sequencing batch reactor (SBR). Results indicate the consortium could grow and effectively remove ammonium when the salt concentration was below 50 g/L. In the range of pH 5.0–10.0, more than 97% NH4+-N was removed by the consortium. Adding 1000 mg/L phenol in the basal medium (BM) had no significant effect on its nitrification ability. However, when phenol was used as the sole carbon source, the removal efficiency of phenol and ammonium decreased with the increase of phenol concentration in the case of 1% inoculum dose, which was improved by increasing the inoculum size. The removal efficiency of phenol, NH4+-N and COD reached 99.63%, 98.41%, and 83.69% when 3% of the consortium was inoculated in actual coking wastewater in the batch test. Bioaugmentation experiment shows that the consortium could effectively improve the simultaneous removal performance of carbon and ammonium in the SBR. [ABSTRACT FROM AUTHOR]

Conventional batch synthesis of hexafluoroacetone (HFA), an important pharmaceutical intermediate, suffers from complex catalyst preparation, harsh reaction conditions (up to 200 °C), and low selectivity. In this study, we developed a continuous flow system that employs a micro packed-bed reactor (MPBR) filled with Lewis acid catalysts. After an initial screening of reaction conditions and catalysts in the batch reactor, a Bayesian Optimization model and the multi-objective optimization algorithm qNEHVI were used to find a compromise between conversion and energy efficiency for the reaction in the continuous flow system. After 14 rounds of experiments, BO found the best results with conversion of 98.6%, selectivity of 99.9%, and an energy cost of 0.121 kWh per kg of product at 25.1 °C, atmospheric pressure, and a GHSV of 931.5 h− 1 reaction conditions. The study demonstrates that BO can be used as an efficient tool for multi-objective optimization of heterogeneous catalysis in continuous flow. [ABSTRACT FROM AUTHOR]

This work is devoted to the synthesis and optimization of methods for obtaining low‑dose hydrate formation inhibitors derived from waterborne polyurethanes. Some monomers were replaced by less expensive reagents that need not be imported to Russia in order to optimize the synthesis of such inhibitors. Two polymerization procedures were tested. One method was carried out in a batch reactor, while the other continuous method was carried out in a flow reactor. A laboratory flow unit was designed to simulate the conditions of the continuous synthesis. [ABSTRACT FROM AUTHOR]

Natural zeolite and sulfated natural zeolite catalyst materials have been successfully prepared, characterized, and applied as a replacement for the role of a sulfuric acid catalyst in the synthesis of nitrobenzene. Natural zeolites were prepared into uniform-sized powders and then refluxed with H2SO4 with varying concentrations of 0, 1, 2, 3, and 4 M, proceeded by calcination with N2 gas flow (labeled as NZ, SNZ-1, SNZ-2, SNZ-3, and SNZ-4). Nitrobenzene was synthesized in a batch microwave reactor using natural zeolite and sulfated natural zeolite catalysts with the best acidity value. The results showed that the sulfuric acid treatment of natural zeolite caused changes in its physical and chemical characteristics. The NZ catalyst has an acidity value of 1.742 mmol g−1, and the 2 M concentration variation resulted in the sulfated natural zeolite with the best acidity value of 1.625 mmol g−1. The optimal amount of catalyst required is 1.0 g. Both catalysts are selective toward the nitration reaction of benzene. The average benzene conversion produced for each catalyst was 41.53 ± 3.61% and 58.92 ± 1.37%. Furthermore, the SNZ-2 catalyst has better reusability for three reaction runs. [ABSTRACT FROM AUTHOR]