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Octyl laurate phase change material (PCM) was microencapsulated by calcium alginate for eco-friendly low temperature energy storage. The PCM microcapsules were prepared by repeated interfacial coacervation followed by crosslinking method. In order to enhance the antibacterial properties of the as prepared capsules, the calcium alginate shell was functionalized by Ag nanoparticles. Calcium alginate-octyl laurate microcapsules possessed high latent heat of fusion values (130.8 and 128.6 J g−1 on melting and cooling, respectively) which did not significantly change when Ag nanoparticles were entrapped in the shell (127.5 and 125.2 J g−1 for melting and freezing enthalpy changes). Based on these values 71.0 and 69.0% maximal PCM content in the microcapsules were determined by the differential scanning calorimetry method. Both of the Ag-loaded and unloaded calcium alginate-octyl laurate PCM capsules maintained the high heat storing capacity after 250 warming and cooling cycles, which proved they did not suffer from leakage after the accelerated thermal test.

Numerous recent studies have shown that discharging colored wastewater into the environment causes contamination, which has adverse impact due to textile, dyeing, and food industries. The current study presents experimental research on the clathrate hydrate technique used for producing pure water from of wastewater contaminated by dyes. Under constant starting conditions, the clathrate formation for binary (water + refrigerant gas) and ternary (water + refrigerant gas + promotor) systems were studied. The R134a gas was used along with Cyclohexane (2.5 vol%), Tween 80 (100 ppm), and silica gel powder as promotors (100 ppm). Moreover, povidone-iodine (500, 2500, and 5000 ppm) and potassium permanganate (10, 50, and 100 ppm) were used as colored compounds in order to prepare synthetic wastewater (model wastewater). The production of hydrates, which rapidly captured the refrigerant gas molecules in the solid phase, was primarily responsible for the pressure drop. Both povidone-iodine and potassium permanganate have a negligible impact on the hydrate formation rates. It was found that the concentration of povidone-iodine and potassium permanganate in the produced water was decreased. As far as we know, the method of using clathrate hydrate to remove the dyes in water has never been investigated. The results showed that the povidone-iodine removal efficiency ranged between 86% and 92%, and the potassium permanganate removal efficiency ranged between 90% and 95%. The removal efficiency was improved by adding promotors, which increased the dissolved gas quantity and the amount of water hydrates. The maximum removal efficiency was accomplished using silica gel powder and cyclohexane, which are more significant than in pure water and Tween 80. This study demonstrated the viability of the clathrate hydrate technique as a green technology for the treatment of colored wastewater effluents from different industries.

In this study, pomegranate peels (PPs) as an abundant fruit processing waste was used to produce cost-effective, eco-friendly, and high-quality activated carbon. The produced carbon (fossil free activated carbon) was used for immobilizing laccase to remove a range of emerging pollutants namely diclofenac, amoxicillin, carbamazepine, and ciprofloxacin from water and wastewater. The loaded activated carbon by laccase (LMPPs) and the unloaded one (MPPs) were characterized using advanced surface chemistry analysis techniques. MPPs was found to have a porous structure with a large surface area and an abundance of acidic functional groups. Laccase immobilization reduced surface area but added active degradation sites. The optimal immobilization parameters were determined as pH 4, 35 oC, and a laccase concentration of 2.5 mg/mL resulting in a 69.8% immobilization yield. The adsorption of the emerging pollutant onto MPPs is best characterized as a spontaneous endothermic process that adheres to the Langmuir isotherm and first-order kinetics. Using synergistic adsorption and enzymatic degradation, the target pollutants (50 mg/L) were eliminated in two hours. In both water types, LMPPs outperformed MPPs. This study shows that pomegranate peels can effectively be harnessed as an enzyme carrier and adsorbent for the removal of emerging pollutants even from a complex sample matrix. The removal of contaminants from wastewater lasted five cycles, whereas it continued up to six cycles for water.

During this research work, the wear and friction properties of TiN/TiC coatings produced with different manufacturing parameters were investigated against steel and zirconium counterparts. The coatings, which were deposited on WC–Co substrate, were characterized based on their microstructure, phase composition, and microhardness. The tribological behavior of the coatings was examined in accordance with ASTM G99 and ASTM G133 standards using pin-on-disc tests with steel and zirconium counterfaces, while the adhesion of the coatings was investigated with a modified scratch test. According to the results obtained from the experiments, the use of zirconium counterpart is advantageous even for coatings produced with different microhardness and layer thickness using the CVD method. The results show that the change in the friction coefficient can be well traced with properly chosen parameters, thereby determining the wear resistance of the coating.

The aim of this study was to investigate the bone-like apatite forming ability of bioglass coated bones by immersing them in simulated body fluid (SBF). Various types of bioactive coatings with an average thickness of 15 ?m were deposited on the surface of the cortical bovine bone by vacuum assisted infiltration.More intense apatite crystallization was observed using additives such as hydroxyapatite, sintered bone and ?-whitlockite in the base glass. The dissolution properties of the scaffolds were determined by ICP-OES and XRF methods. The consequence of the release of Ca and P during immersion in SBF on the mechanical properties was observed through measurements of microhardness, bending and compressive strength.

Bioactive glass-ceramic coated 3D scaffolds with proper mechanical properties were fabricated. The base material of the scaffold is bovine bone, which appears mainly as a waste of the meat processing industry. After pre-treatment, different glass-ceramic mixtures were deposited onto the surface of these bones by infiltration in a vacuum chamber to form a smooth layer having a thickness of about 20 ?m. This coating has a beneficial effect both on the hardness and bending strength, and has bioactive properties to promote the colonization of bone-forming cells. Therefore, a scaffold that provides mechanical support and is biodegradable, was achieved with the bovine bone - glass-ceramics composites. Structure and properties of the composite scaffolds were tested by imaging methods (SEM, LM, CT), chemical and phase composition (EDS, XRD), strength, hardness and specific surface area measurements. In vitro cytotoxicity and cell adsorption were tested using colon adenocarcinoma tumour cells.

Funding Information: The ÚNKP-22–3-I-PE-12 (Osamah J. Al-sareji) New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund supported this research. Publisher Copyright: © 2023 The Authors This work reports the removal of diclofenac, amoxicillin, carbamazepine, and ciprofloxacin by utilizing three commercially available granular activated carbons (GACs) (Activated carbon, Silcarbon, and Donau) loaded with laccase. Adsorption was used to successfully immobilize laccase on the GACs, as revealed by scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) and Fourier transform infrared spectroscopy (FTIR). In the three types of GACs tested, pH 5, 30 °C, and 2 mg mL−1 laccase content were found to be the optimum immobilization parameters. Laccase immobilization yields of 65.2%, 63.1%, and 62.9% were achieved with activated carbon, Silcarbon, and Donau respectively. The adsorption behaviors of the pharmaceuticals onto the tested activated carbons are best described as a spontaneous endothermic process that follows Langmuir isotherm and first-order kinetics. The reusability of the immobilized enzyme was evaluated using 2, 2′-azino-bis 3-ethylbenzothiazole-6-sulphonic acid (ABTS) as a substrate within six cycles for all adsorbents. In 120 mins, nearly a complete removal of the pharmaceutical compounds (50 mg L−1) was obtained in the case of activated carbon type and more than 90% for other adsorbent types when synergistic adsorption and enzymatic degradation were applied. With adsorption alone, 74% removal was obtained with activated carbon and < 56% for other adsorbents. The finding of this study suggests that biochar produced from coconut shell (same as the one used in this study) can effectively be used as a substrate and adsorbent for pharmaceutical removal. This enzymatic physical removal system has the potential to be applied on a large-scale.

Funding Information: First and foremost, we are grateful to the anonymous reviewers for improving the paper's quality. The authors acknowledge the support in the form of various facilities provided by Aalto University, Finland and Liverpool John Moores University, UK. We also appreciate the facilities provided by the Environmental Research and Studies Center (ERSC), University of Babylon, Iraq. This article represents the views or opinions of its authors. Funding Information: The ÚNKP-22-3-I-PE-12 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund supported this research. The study was partially supported by the Stipendium Hungaricum, and the Environmental Research and Studies Center, University of Babylon. Publisher Copyright: © 2022 The Authors In recent years, enzymatic remediation/biocatalysis has gained prominence for the bioremediation of recalcitrant chemicals. Laccase is one of the commonly investigated enzymes for bioremediation applications. There is a growing interest in immobilizing this enzyme onto adsorbents for achieving high pollutant removal through simultaneous adsorption and biodegradation. Due to the influence of the biomolecule-support interface on laccase activity and stability, it is crucial to functionalize the solid carrier prior to immobilization. Date stone (PDS), as an eco-friendly, low-cost, and effective natural adsorbent, was utilized as a carrier for laccase (fungus Trametes versicolor). After activating PDS through chemical treatments, the surface area increased by thirty-six-fold, and carbonyl groups became more prominent. Batch experiments were carried out for ketoprofen and aspirin biodegradation in aqueous solutions. After six cycles, the laccase maintained 54% of its original activity confirmed by oxidation tests of 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). In addition, the storage, pH, and thermal stability of immobilized laccase on functionalized date stone (LFPDS) were found to be superior to that of free laccase, demonstrating its potential for ongoing applications. In the aqueous batch mode, this immobilized laccase system was used to degrade 25 mg L−1 of ketoprofen and aspirin, resulting in almost complete removal within 4 h of treatment. This study reveals that agricultural wastes such as date stone can successfully be valorized through simple activation techniques, and the final product can be used as an adsorbent and substrate for immobilization enzyme. The high efficiency of the LFPDS in removing ketoprofen and aspirin highlights the potential of this technology for removing pharmaceuticals and merits its continued development.

Nanostructured composites containing iron oxide and hydroxyapatite (m-HA) were prepared by two wet chemical methods (single-step and double-step process) having different order of magnetite and HA precipitations. The phase composition, crystal size and lattice constants of the prepared composites were determined by XRD, the functional groups by FTIR and the structure, morphology and elemental composition by TEM. The magnetic susceptibility values and the colour indexes of each composite were also determined. Biocompatibility testing was performed in simulated body fluid. The results show that the composites produced by different (single-step and double-step) co-precipitating methods show different chemical and phase composition, average particle size, and therefore different superparamagnetic properties and bioactivities, with possibilities for different applications.

We studied the fabrication of functionally graded Al2O3–CeO2-stabilized-ZrO2 (CTZ) ceramics by spark plasma sintering. The ceramic composite exhibits a gradual change in terms of composition and porosity in the axial direction. The composition gradient was created by layering starting powders with different Al2O3 to CTZ ratios, whereas the porosity gradient was established with a large temperature difference, which was induced by an asymmetric graphite tool configuration during sintering. SEM investigations confirmed the development of a porosity gradient from the top toward the bottom side of the Al2O3–CTZ ceramic and the relative pore volume distributed in a wide range from 0.02 to 100 µm for the samples sintered in asymmetric configuration (ASY), while for the reference samples (STD), the size of pores was limited in the nanometer scale. The microhardness test exhibited a gradual change along the axis of the ASY samples, reaching 10 GPa difference between the two opposite sides of the Al2O3–CTZ ceramics without any sign of delamination or cracks between the layers. The flexural strength of the samples for both series showed an increasing tendency with higher sintering temperatures. However, the ASY samples achieved higher strength due to their lower total porosity and the newly formed elongated CeAl11O18 particles.

We studied the fabrication of functionally graded Al

Photocatalytic H2 production utilizing H2S, an industrial side-product, is regarded as an environmentally friendly process to produce clean energy through direct solar energy conversion. For this purpose, sulfide-based materials, such as photocatalysts, have been widely used due to their good solar response and high photocatalytic activity. In this work, a ZnS–CdS composite was studied, and special attention was dedicated to the influence of the preparation parameters on its H2 production activity. The ZnS–CdS composite, with an enhanced photoactivity for H2 production, was synthesized both from ammine complexes and, in a conventional way, directly from acetates at various pH values. Deviating from the traditional method, the photoactivity of ZnS–CdS prepared from ammine complexes was not affected by the pH. Besides, the hydrothermal treatment and the ammonia content strongly influenced the rate of H2 production in this system. DRS, TEM, SEM, XRD, and quantum yield measurements prove the dependence of the photoactivity of these catalysts on the structural and morphological properties determined by the preparation conditions. The promising photocatalytic efficiency achieved with the application of these ZnS–CdS catalysts, prepared without any metal deposition, encourages further investigations to enhance the rate of hydrogen generation by optimization of the reaction conditions for practical utilization.

In this paper, the application of multiwalled carbon nanotubes (MWCNTs) based on metal oxide nanocomposites as adsorbents for the removal of hydrocarbons such as kerosene from water was investigated. Functionalized MWCNTs were obtained by chemical oxidation using concentrated sulfuric and nitric acids. V2O5, CeO2, and V2O5:CeO2 nanocomposites were prepared using the hydrothermal method followed by deposition of these oxides over MWCNTs. Individual and mixed metal oxides, fresh MWCNTs, and metal oxide nanoparticle-doped MWCNTs using different analysis techniques were characterized. XRD, TEM, SEM, EDX, AFM, Raman, TG/DTA, and BET techniques were used to determine the structure as well as chemical and morphological properties of the newly prepared adsorbents. Fresh MWCNTs, Ce/MWCNTs, V/MWCNTs, and V:Ce/MWCNTs were applied for the removal of kerosene from a model solution of water. GC analysis indicated that high kerosene removal efficiency (85%) and adsorption capacity (4270 mg/g) after 60 min of treatment were obtained over V:Ce/MWCNTs in comparison with fresh MWCNTs, Ce/MWCNTs and V/MWCNTs. The kinetic data were analyzed using the pseudo-first order, pseudo-second order, and intra-particle diffusion rate equations.

The industrial and environmental applications of laccase, especially in wastewater treatment, have gained focus in recent years. Therefore, developing the proper laccase immobilization techniques, which could improve the stability of the enzymes and simplify the required downstream processes, is needed. A novel two-step immobilization process was developed, resulting in cross-linked enzyme aggregates (CLEA) in the pores of the membrane. Laccase adsorption on a biodegradable cellulose acetate microfiltration membrane along with cross-linking was investigated to maximize the enzyme load and immobilization efficiency. The optimization was done regarding the: pH, temperature, enzyme concentration, adsorption time, cross-linker concentration, and temperature. It was concluded that the highest immobilization efficiency (76%) could be achieved in acidic buffers at 29 °C with high surface activity (1174 U·m−2) at the cost of partial denaturation and membrane fouling. The membrane was successfully utilized for the enzymatic treatment of diclofenac, and 58% removal efficiency was achieved. The results indicated that cellulose acetate is a suitable carrier for adsorption-based immobilization of laccase for the potential for environmental utilisation.

Nowadays, global warming and the ensuing climate change are one of the biggest problems for humanity, but environmental pollution and the low ratio of waste management and recycling are not negligible issues, either. By producing alkali-activated cements (AACs), it is possible to find an alternative way to handle the above-mentioned environmental problems. First, with a view to optimizing experimental parameters, metakaolin-based AACs were prepared, and in it, waste tire rubber was used as sand replacement (5–45 wt %). Insufficient wetting between the rubber particles and the matrix was corrected through different surface treatments of the rubber. For improving the mechanical/strength properties of the specimens, fibrous waste kaolin wool (0.5–1.5 wt %) was added to the AAC matrix. Considering the results of model experiments with metakaolin, blast-furnace-slag-based AAC composites were developed. The effects of storage conditions, specimen size and cyclic loading on the compressive strength were investigated, and the resulting figures were compared with the relevant values of classic binders. The strength (44.0 MPa) of the waste-based AAC composite significantly exceeds the required value (32.5 MPa) of clinker saving slag cement. Furthermore, following cyclic compressive loading, the residual strength of the waste-based AAC composite shows a slight increase rather than a decrease.

Six silica-supported phosphotungstic acid catalysts (PTA/SiO2) of different composition (20–70 wt% PTA content) have been synthesized and characterized by elemental analysis, BET, BJH, NH3-TPD methods, FT-IR spectroscopy of adsorbed pyridine and 1H MAS NMR techniques. The new composite catalysts were first applied in the Friedel–Crafts alkylation of toluene with 1-octene as a benchmark process under batch conditions in order to screen their activity and recyclability. The combined analytical techniques together with the catalytic studies enabled the identification of the main factors affecting the activity of the catalysts. Based on these preliminary experiments, the best performing catalyst system (50 wt% PTA/SiO2) was investigated in continuous flow mode using an in-house-made flow reactor. The thorough screening of the reaction conditions (temperature, toluene/1-octene molar ratio and flow rate) provided firm evidence that the 50 wt% PTA/SiO2 composite is highly active, selective and stable catalyst under mild reaction conditions even at elevated flow rate. Additionally, the catalyst used in the flow mode could successfully be regenerated and reused in the alkylation process.

Biocatalytic kinetic effect of a-chymotrypsin enzyme has been investigated in its free and pretreated forms (it was covered by a very thin, porous polymer layer, called enzyme nanoparticle) as well as its immobilized form into pores of polysulfone/polyamide asymmetric, hydrophilic membrane. Trimethoxysilyl and acrylamide-bisacrylamide polymers have been used for synthesis of enzyme nanoparticles. Applying Michaelis-Menten kinetics, the KM and vmax values of enzyme-polyacrylamide nanoparticles are about the same, as that of free enzyme. On the other hand, enzyme nanoparticles retain their activity 20&ndash, 80 fold longer time period than that of the free enzyme, but their initial activity values are reduced to 13&ndash, 55% of those of free enzymes, at 37 &deg, C. Enzyme immobilized into asymmetric porous membrane layer remained active about 2.3-fold longer time period than that of native enzyme (at pH = 7.4 and at 23 &deg, C), while its reaction rate was about 8-fold higher than that of free enzyme, measured in mixed tank reactor. The conversion degree of substrate was gradually decreased in presence of increasing convective flux of the inlet fluid phase. Biocatalytic membrane reactor has transformed 2.5 times more amount of substrate than the same amount of enzyme nanoparticles and 19 times more amount of substrate than free enzyme, measured in mixed tank reactor.

In order to extend the photoactivity of titanium dioxide into the visible region, highly porous nitrogen-doped TiO2 catalysts (NTiO2) were successfully synthesized by a modified co-precipitation method with ammonium hydroxide as a nitrogen source. Different approaches such as dosing order of the reagents and temperature of the synthesis, calcination period and temperature were tested to examine the optimum outcome regarding photocatalytic OH radical formation under UV and visible light. Coumarin as a traditional probe for this purpose was applied; measuring the luminescence of 7-hydroxycoumarin produced in the reaction with OH radicals, beside the formation of other hydroxylated derivatives. Only a few percentages of the coumarin molecules reacted with OH radicals, while most of them underwent reactions with other photogenerated species such as electrons (anaerobic/aerobic) and superoxide anion radicals (aerobic). Accordingly, our observations suggest that coumarin can also be used as a probe to quantify the formation of other reactive species. The results were obtained from the difference between the amounts of degraded coumarin and hydroxylated coumarin derivatives formed during photocatalytic experiments. These coumarin-based quantifications of photoactivity was applied for the characterization of the prepared nitrogen-doped TiO2 catalysts (NTiO2). In addition, material analysis (X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometry, and Fourier transform infrared spectroscopy) showed that crystallinity and nitrogen content were found to be crucial features in the photocatalytic performance of the catalysts.

The application of a sol-gel method, starting from N-(4-ferrocenyl-6-phenylpyrimidin-2-yl)-N’-(3-(triethoxysilyl)prop-1-yl)-urea (4), tetraethoxysilane and a structure directing agent, led to the formation of hollow spherical particles with organic moieties concentrated on the inner surface. A similar sol-gel electrodeposition technique was used for the modification of the surface of a spectral graphite electrode. The solid materials were characterized by solid phase NMR and IR measurements, thermal analysis, SEM and TEM. The functional group attached to the ferrocene core offers the possibility to form H-bonds with various guest molecules that makes it a potential electrochemical sensor.