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Herein, novel cellulose-based biosorbent with dual-particles system was fabricated through a rapid and facile etching-loading method. The results shown the adsorbent exhibited efficient and stable adsorption performance which is owing to the firm embedding of functional particles without interference on the oxidized matrix. And the maximum adsorption capacity for Pb2+ reached 372.4 mg/g. The corresponding adsorption behavior was found to accord well with the pseudo-second-order kinetic model and Langmuir isotherm model, which reveals the rate-limiting phase of adsorption process is attributed to chemical adsorption type, and Pb2+ was adsorbed onto biosorbent surface by monolayer spontaneous chemical reaction. Surface physical attraction and chemical complexation bond are dominant adsorption mechanisms. And the recycling efficiency of biosorbent reached above 83% after 5 cycles. The above results indicate the hybrid functional structure by etching-loading route provided a novel method for rapid construction of promising and recyclable adsorbent for wastewater treatment. [ABSTRACT FROM AUTHOR]

In the contemporary landscape, the reuse of wastewater holds paramount significance. Concurrently, wastewater carries an array of pollutants encompassing chemical dyes and heavy metals. This study delves into the potential of Tamarix aphylla (TA) and Eucalyptus camaldulensis (EC) species for mitigating heavy metals in soil and eliminating methylene blue dye (MB) from wastewater. The research begins with assessing the dye adsorption process, considering pivotal factors such as initial pH, adsorbent dosage, initial dye concentration, and contact time. Outcomes reveal EC's superiority in dye removal compared to TA. As a bioremediation agent, EC exhibits a 90.46% removal efficacy for MB within 15 min, with pH 7.0 as the operative condition. Equilibrium analysis employs Temkin (T), Freundlich (F), and Langmuir (L) isotherms, revealing an excellent fit with the L isotherm model. The study delves further by probing surface adsorption kinetics through pseudo-first-order (PFO) and pseudo-second-order (PSO) models. Furthermore, to discern the divergent impacts of EC and TA on soil heavy metal reduction, soil samples were collected from three distinct zones: an untouched control area, alongside areas where EC and TA were cultivated at the Yazd wastewater site in Iran. Heavy metal levels in the soil were meticulously assessed through rigorous measurement and statistical scrutiny. The findings spotlight TA-cultivated soil as having the highest levels across all examined factors. Ultimately, EC emerges as the superior contender, proficiently excelling in both MB eliminations from wastewater and heavy metal amelioration in the soil, positioning it as the preferred phytoremediation agent. [ABSTRACT FROM AUTHOR]

Natural biosorbents from agricultural side stream products are being investigated due to their large surface area and capacity for various compounds. The aim of the present work was to investigate the raspberry seeds and their sorption potential in the recovery of natural pigments. The experiment included raspberry seed and a liquid by-phase rich in anthocyanins initially collected during the depulping of the raspberry seed material. Biosorption was monitored by LC-MS analysis of the anthocyanins and by the total anthocyanin content (TAC) before and after biosorption. Cyanidins predominated in the seed material, followed by pelargonidins and peonidins. The efficiency of biosorption was examined by comparing the percent of removal. The heterogeneous polymer structure of the biosorbent, which consists mainly of lignin, cellulose, and hemicellulose, was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy (RS). The FTIR spectra of raw and defatted seed indicated functional groups involved in biosorption and principal component analysis (PCA) performed on Raman spectra pointed to differences among biosorbents. The developed strategy for the valorization of raspberry seeds in the recovery of natural colorants was shown to be effective, with recoveries from 49 to 88 percent of total anthocyanins. [ABSTRACT FROM AUTHOR]

Cadmium (Cd(II)) contamination is very harmful to the aquatic environment. Currently, the removal of Cd(II) from water is widely studied to reduce its toxicity. In this study, agricultural waste sorghum bagasse (SB) was activated with NaOH and used to adsorb Cd(II) in aqueous solution. NaOH-activated sorghum bagasse (SB-NaOH) was characterised using Fourier transform infrared spectroscopy (FTIR) to investigate the functional groups, scanning electron microscopy (SEM-EDX) to observe surface morphology, X-ray diffraction (XRD) to analyzed the structure and chemical composition, and Brunauer–Emmett–Teller (BET) method to evaluate pore size. The batch system was used to investigate the adsorption parameters such as adsorbent mass, contact time, initial concentration, pH, and temperature. The optimum conditions of Cd(II) adsorption were at pH 5, 70 min, 600, 100 mg/L, and 30°C. The maximum adsorption percentage was 96.48%. The pseudo-second-order is suitable for kinetic models of Cd(II) adsorption and the isotherm model was Langmuir model. The Gibbs free energy obtained a positive value and the enthalpy had a negative value, indicating that the adsorption of Cd(II) is an exothermic process. Therefore, SB-NaOH adsorbent can be used as a potential adsorbent with easy and economical treatment to reduce Cd(II) in the aquatic environment. [ABSTRACT FROM AUTHOR]

Dyes are widely used in manufacturing of various consumer products for their ability to impart characteristic color. However, dyes are also one of the most important hazardous pollutants in this present day. Presence of hydroxyl, phosphate, ether, carbonyl and alkyl groups also enable bacterial extracellular polymers to function as biosorbent. In this study, negatively charged biosorbent EP-C1 produced by Gram-negative bacterium Ochrobactrum pseudintermedium C1 utilizing waste mineral lubricating oil has given different decolorization percentages for triphenylmethane cationic Malachite Green and azoic anionic Congo Red at neutral pH. Time wise absorbances from Ultraviolet-Visible Spectrophotometry has estimated maximum biosorption of Malachite Green after 300 min. Biosorption capacities have differed with initial dye concentrations, biosorbent dosages and contact time. Time taken by each dye to reach saturation has depended upon their charged bearing groups of each dye and biosorbent. Kinetic (pseudo first and pseudo second order) and diffusion (intra particle and liquid film) parameters in presence of different dye concentrations and biosorbent dosages were studied for understanding the biosorption mechanism. Morphological differences in chemical structure, chemical functional groups of EP-C1 and EP-C1 loaded dye was studied by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and Zeta potential measurements. A compiled overview on comparative mechanistic biosorption of Malachite Green and Congo Red dyes by a bacterial extracellular polymer in miniature laboratory shake flask experiments was done in this study. Newer advents on biological remediation of dyes with mineral lubricating oil as sole carbon source can add a new feather to the already available bioremediation techniques in mitigation of hazardous wastes. [ABSTRACT FROM AUTHOR]

Elements are released into water bodies, affecting the environment and human health. To address this problem, the adsorption-desorption capacity of untreated rice husk (URH) and rice husk treated with alkali (RHTA) for Cu(II), Pb(II), Fe(II), Cd(II), and Zn(II) was investigated. Analyses during the process were performed by X-ray diffraction (XRD), scanning electron microscopy, and elemental analysis by energy dispersive X-ray spectroscopy (SEM-EDS), as well as Fourier transform infrared spectroscopy (FTIR). Adsorption-desorption kinetics and isotherms were carried out. The FTIR analysis of RHTA revealed a lowering of intensity of the bonding signals (OH, C-O, CH2, CH3, SiO2, Si-OH) and loss of some signals due to the adsorbent-elements interaction. The adsorption on RHTA presented higher adsorption of Fe, followed by Pb, Zn, Cu, and Cd. Meanwhile, in URH, the adsorption was Fe > Pb > Cu > Zn and Cd. On the other hand, the desorption values for RHTA were Zn > Cd > Pb > Cu > and Fe and Zn > Cd > Cu > Pb and Fe for URH. The adsorption kinetics showed that data fit (R2 ≥ 0.89) to pseudo-second-order kinetics and Freundlich isotherms (R2 ≥ 0.84) for both ATRH and URH, indicating that the process occurs in the multilayer form and is controlled by chemisorption, where the adsorption depends on the active sites of the adsorbent surface. [ABSTRACT FROM AUTHOR]

All pests can be eliminated with the help of pesticides, which can be either natural or synthetic. Because of the excessive use of pesticides, it is harmful to both ecology and people's health. Pesticides are categorised according to several criteria: their chemical composition, method of action, effects, timing of use, source of manufacture, and formulations. Many aquatic animals, birds, and critters live in danger owing to hazardous pesticides. Metaldehyde is available in various forms and causes significant impact even when small amounts are ingested. Metaldehyde can harm wildlife, including dogs, cats, and birds. This review discusses pesticides, their types and potential environmental issues, and metaldehyde's long-term effects. In addition, it examines ways to eliminate metaldehyde from the aquatic ecosystem before concluding by anticipating how pesticides may affect society. The metal–organic framework and other biosorbents have been appropriately synthesized and subsequently represent the amazing removal of pesticides from effluent as an enhanced adsorbent, such as magnetic nano adsorbents. A revision of the risk assessment for metaldehyde residuals in aqueous sources is also attempted. [ABSTRACT FROM AUTHOR]

Agricultural residues, specifically canola meal (CM) and oat hull (OH), have been innovatively utilized to develop biosorbents for sorbing water vapor from the air. These biomaterials are comprised of hydrophilic functional groups that effectively perform air dehydration. Air, being non-polar, was used as a model gas in this study to simulate gas dehydration. In the current research, these materials were formed into pellets to produce high-quality biosorbents with controlled size, shape, and enhanced moisture uptake capacity. CM (309.48 mg/g) and OH (233.07 mg/g) pellets had higher or comparable water sorption capacities than commercialized adsorbents used for drying gases. The mixed-order kinetic model described the sorption process well and identified both mass transfer and sorption on active site steps (R2 > 0.991 and χ2 < 16.0). Regarding the OH pellet, sorption on active sites was the predominant kinetic mechanism at the beginning, followed by intraparticle diffusion until equilibrium. However, sorption on CM pellets was delayed at 4.2 min at the initial stage, owing to the external mass transfer resistance; then, intraparticle diffusion controlled the process until equilibrium. Adding sodium lignosulfonate (LSNa) lowered the initial sorption rate but enhanced the water uptake and strength of pellets. The addition of LSNa resulted in a 25% and 14% increase in the water uptake capacity of oat hull and canola meal pellets, respectively; conversely, it also caused an increase in the delay time for sorption on CM pellets at the beginning of the process, extending it to 9.50 min. [ABSTRACT FROM AUTHOR]

The urgent need for technological innovation to combat water pollution underscores the significance of biosorption as a potential solution. The success of biosorption hinges on the careful selection of a suitable biosorbent. Biofilms, composed of microbial communities, emerge as a promising alternative due to their expansive adsorption capacity and ready availability. In practical applications, biosorption is often executed at pollutant concentrations lethal to microbes. Consequently, comprehending the biosorption potential of biofilms with deceased microbes becomes imperative. Notably, biofilms with deceased microbes offer the added advantage of minimizing the risk of pathogenic microbial contamination. Despite this, studies are scarce comparing biosorption between intact biofilms and those with deceased microbes. This comparative analysis could enhance the feasibility of biofilms in biosorption as an eco-aquatic technology for alleviating aquatic pollution. This study aims to scrutinize the biosorption characteristics of intact biofilm (with living microbes) and autoclaved biofilm (with deceased microbes). The methods employed for analyzing biosorption characteristics encompass examining electric charge properties, FTIR spectra analysis, ion adsorption, and ion desorption. The model ions chosen for this study are K⁺ (monovalent ion) and Mg²⁺ (divalent ion). Results indicate that the biofilm's electric charge properties and adsorption capacity remain relatively unchanged post-autoclaving. Based on these findings, it can be concluded that biofilms, whether intact or autoclaved, present substantial potential as biosorbents in the advancement of eco-aquatic technology for mitigating water pollution.

Our study aims to investigate the response of the unicellular alga, Haematococcus pluvialis, to the toxicity of lead and propose a low-cost, highly efficient biological adsorbent for the purification of wastewater and lead-contaminated water. The first part examines the effects of lead toxicity on certain physiological indicators of this alga. In the second part, the potential of this alga in lead removal and its adsorption capacity was assessed. The alga was cultivated in a BG11 medium and treated with lead nitrate concentrations of 10, 50, and 200 mg/L during its exponential growth. The results showed that with an increase in lead concentration up to 200 mg/L, the growth rate, chlorophyll a, chlorophyll b, carotenoid and total protein content decreased, while malondialdehyde (MDA) content increased. The astaxanthin content slightly increased at the 10 mg/L but decreased at the 200 mg/L treatment. Maximum lead adsorption was observed at 98.69% under optimal conditions, including a pH of 6, an adsorbent dose of 1 g/L, a lead concentration of 25 mg/L, a temperature of 25 °C, and an exposure time of 120 min. The results of this study demonstrate that Haematococcus pluvialis has the potential for effective lead removal from aquatic environments. While the influence of heavy metals on certain algae species has been explored, research on the impact of lead on Haematococcus pluvialis—a microalga of significant interest for astaxanthin production—remains uncharted territory. Therefore, understanding the impact of this heavy metal and the alga's metal absorption capabilities has profound implications for biotechnology and bioremediation applications. This study promotes H. pluvialis as an economically viable lead absorbent suitable for both industrial and domestic purposes. [ABSTRACT FROM AUTHOR]

Low-quality cotton fibers are a low-value waste material within the cotton industry. Upcycling and transforming into high-value materials are highly desired. This study investigates upcycling fibers into hydrogel biosorbents and assesses their efficacy in dye adsorption. An effective gelation approach was employed via simply dropping droplets of suspension mixture of sodium alginate and fibers into acidic bath. Resulting composite hydrogel beads were utilized for dye removal. Composite beads successfully immobilized less than 70 wt% of fibers and achieved a significant improvement in thermal stability. Composite beads with 50 wt% fibers and alginate showed no decrease in methylene blue adsorption capacity. This outcome was unexpected considering the lower dye adsorption capacity of fibers than alginate, particularly notable since it indicated that reduced quantities of the more costly sodium alginate were sufficient to achieve comparable dye adsorption capacity. Mechanistic study unveiled that both the loose crosslinking structure and the electrostatic forces were responsible for the unexpected high adsorption capacity of 50% fiber-alginate. This study reports a promising, innovative and effective upcycle strategy for the first time that can transform fibers into high-value biosorbents without compromising dye adsorption capability. [ABSTRACT FROM AUTHOR]

The aim of the research was to prepare silica adsorbents using an environmentally friendly pathway, a template synthesis with saponin biosurfactant as a structure-directing agent. The adsorbents prepared in this way exhibit improved adsorption properties while maintaining environmental innocuousness. For the preparation of porous silica, the biosurfactant template sol–gel method was used with tetraethoxysilane as a silica precursor. The silica adsorbents were analyzed by FTIR spectroscopy, nitrogen adsorption–desorption and SEM/EDX microscopy, TEM/HRTEM microscopy, and thermogravimetric analyses. Batch tests were carried out to remediate Pb(II)/Cd(II) ions in single/binary aqueous solutions, and the effect of the surfactant on the adsorption properties was assessed. The optimal adsorption parameters (pH, contact time, initial concentration of metal ions) have been determined. The adsorption was fitted using Langmuir and Freundlich adsorption isotherms and kinetic models. Mathematical modeling of the retention process of Pb(II) and Cd(II) ions from binary solutions indicated a competitive effect of each of the two adsorbed metal ions. The experimental results demonstrated that saponin has the effect of modifying the silica structure through the formation of pores, which are involved in the retention of metal ions from aqueous solutions and wastewater. [ABSTRACT FROM AUTHOR]

Abstract\nNOVELTY STATEMENTThe growth of industrial activities, has led to a significant increase in the influx of color pollutants into the environment. Phytoremediation can play a crucial role in enhancing wastewater quality. Accordingly, this study sought to evaluate the effectiveness of Alhagi maurorum plant powder in removing Janus Green B (JGB) dye from aqueous solutions. The adsorbent’s properties were characterized through Fourier-transform infrared spectroscopy. The study examined various parameters, including initial dye concentration (20–110 mg/L), adsorbent dosage (0.002–0.02 g), solution pH (2–10), and contact time (5–50 min). The experiments revealed that the maximum dye removal efficiency, 99.51%, was achieved under optimal conditions: pH 7, a contact time of 20 min, an adsorbent dosage of 0.01 g, and an initial dye concentration of 90 mg/L. The adsorption of JGB onto the adsorbent followed the Langmuir isotherm model, with a maximum adsorption capacity of 90.909 mg/g. The kinetic results supported a pseudo-second-order model for the adsorption process, with an R2 value of 0.9999. The calculated Gibbs free energy changes (ΔG°) at temperatures of 288, 298, 308, 318, and 328 K were found to be −5354.28, −5993.61, −6439.66, −7026.51, and −7932.05 kJ/mol, respectively, indicating the spontaneity of the adsorption process.This study investigated the capabilities of Alhagi maurorum species for removing Janus Green B in wastewater, because A. maurorum is considered a weed in fields and can be found in abundance in desert areas. It is a low-cost and eco-friendly adsorbent. [ABSTRACT FROM AUTHOR]

Adsorption is one of the most efficient methods for remediating industrial recalcitrant wastewater due to its simple design and low investment cost. However, the conventional adsorbents used in adsorption have several limitations, including high cost, low removal rates, secondary waste generation, and low regeneration ability. Hence, the focus of the research has shifted to developing alternative low-cost green adsorbents from renewable resources such as biomass. In this regard, the recent progress in the modification of biomass-derived adsorbents, which are rich in cellulosic content, through a variety of techniques, including chemical, physical, and thermal processes, has been critically reviewed in this paper. In addition, the practical applications of raw and modified biomass-based adsorbents for the treatment of industrial wastewater are discussed extensively. In a nutshell, the adsorption mechanism, particularly for real wastewater, and the effects of various modifications on biomass-based adsorbents have yet to be thoroughly studied, despite the extensive research efforts devoted to their innovation. Therefore, this review provides insight into future research needed in wastewater treatment utilizing biomass-based adsorbents, as well as the possibility of commercializing biomass-based adsorbents into viable products. [ABSTRACT FROM AUTHOR]

As one of the most promising groups of microbes, lactic acid bacteria (LAB) can synthesize metabolites that can be used in different industries over the world, mainly in the pharmaceutical, food, and dairy industries. In this study, a novel exopolysaccharide was extracted and isolated from the probiotic strain Lactobacillus reuteri B2, and assessed on biological activity and its possible application as a biosorbent for the removal of Ni2+ ions from contaminated water. New exopolysaccharide was characterized using FTIR, SEM, XRD, NMR, MALDI-TOF MS, and TGA/DTG analysis. Biological assays included antioxidative activity, cytotoxic assay, and adhesion assay of L. reuteri B2 to HT29 cells. Our hypothesis was that if this exopolysaccharide is nontoxic, it can be used as a novel biomaterial for the possible application of the removal of Ni2+ ions from contaminated water. The scavenging effect of nontoxic exopolysaccharide was 76% at 2 mg/mL using ABTS assay, in biological assays, while the removal efficiency of nickel from the aqueous solution was 92.96% in biosorption study. According to these results, this exopolysaccharide can be considered a very promising biomaterial for potential application in different industries, from pharmacy to wastewater treatments. [ABSTRACT FROM AUTHOR]

Cobalt pollution is harmful to both the aquatic ecosystem and human health. As the primary producer of aquatic ecosystems in hypersaline environments, unicellular planktonic Dunaliella microalgae is considered to be a low-energy and eco-friendly biosorbent that removes excess cobalt and enhances the vitality of coastal and marine ecosystems. In this study, we found that the halotolerant microalga named Dunaliella sp. FACHB-558 could grow under a salinity condition with 0.5-4.5M NaCl. A phylogenetic analysis based on the rbcL gene revealed that Dunaliella sp. FACHB-558 is a close relative of Dunaliella primolecta TS-3. At labscale culture, Dunaliella sp. FACHB-558 exhibited high tolerance to heavy metal stresses, including cobalt, nickel, and cadmium. Treatment with 60 μM cobalt delayed its stationary phase but ultimately led to a higher population density. Furthermore, Dunaliella sp. FACHB-558 has the ability to adsorb the cobalt ions in the aquatic environment, which was evidenced by the decreased amount of cobalt in the culture medium. In addition, the tolerance of Dunaliella sp. FACHB-558 to cobalt stress was correlated with enhanced nitric oxide content and peroxidase activity. The autophagy inhibitor 3-MA enhanced nitric oxide burst, increased peroxidase activity, and accelerated the bioremoval of cobalt, suggesting that the autophagy pathway played a negative role in response to cobalt stress in Dunaliella sp. FACHB-558. In summary, our study identified a novel microalga possessing high cobalt tolerance and provided a promising natural biosorbent for the research and application of heavy metal bioremediation technology. [ABSTRACT FROM AUTHOR]

Dye effluents cause diverse environmental problems. Methylene blue (MB) dye stands out since it is widely used in the textile industry. To reduce the pollution caused by the MB, we developed biosorbents from tucumã seeds, where the in natura seeds were treated with NaOH (BT) and H3PO4 (AT) solutions and characterized by Boehm titration, point of zero charges, FTIR, TGA, BET, and SEM. It was observed that the acid groups predominate on the surface of the three biosorbents. The process was optimized for all biosorbents at pH = 8, 7.5 g/L, 240 min, C0 = 250 mg/L, and 45 ℃. BT was more efficient in removing MB (96.20%; QMax = 35.71 mg/g), while IT and AT removed around 60% in similar conditions. The adsorption process best fits Langmuir and Redlich-Peterson isotherms, indicating a hybrid adsorption process (monolayer and multilayer) and pseudo-second-order kinetics. Thermodynamic data confirmed an endothermic and spontaneous adsorption process, mainly for BT. MB was also recovered through a desorption process with ethanol, allowing the BT recycling and reapplication of the dye. Thus, an efficient and sustainable biosorbent was developed, contributing to reducing environmental impacts. [ABSTRACT FROM AUTHOR]

The removal of benzene contaminants from synthetic hydraulic fracking water was studied using dried marine macroalgae (ALG) and dodecyl sulphate surfactant-modified marine macroalgae (ALG-SDS). The study assessed the influence of key parameters, including initial benzene concentration, dose of sorbents, contact time, pH, temperature and ionic strength of the fracking solution. The obtained results highlighted the significance of all these factors in the removal process. After thorough experimentation, the optimal conditions for effective removal were determined to be a pH of 5, ALG and ALG-SDS doses of 0.5 g (100 mL volume of solution), an initial benzene concentration of 50 ppm, and a contact time of 90 min. At these optimal conditions, the maximum benzene uptake capacities (qe) were found to be 81 and 85 mg/g for ALG and ALG-SDS, respectively. The removing benzene was effectively described by the pseudo-second-order model, and the Langmuir isotherm model provided a satisfactory fit for the adsorption process. The calculated thermodynamic parameters, including ΔG° (Gibbs free energy change), ΔH° (enthalpy change), and ΔS° (entropy change), indicated that the adsorption of benzene was not only feasible but also spontaneous and exothermic within the temperature range of 283 to 303 K. The structures and morphology were investigated by FTIR, SEM, and BET. Furthermore, regeneration studies were conducted to assess the reusability of the sorbents. The outcomes of this study underscore the effectiveness of employing cost-effective and environmentally friendly waste materials as a viable option for adsorption processes and the remediation of contaminated water. This suggests that utilizing such waste materials holds promise as a sustainable solution for addressing water pollution concerns. This indicated that the sorption process was efficient and suitable for the removal of benzene from the aqueous solution. [ABSTRACT FROM AUTHOR]

Waste from the broiler and layer farming industry with a closed-house system continues to increase without optimizing waste utilization and harms the environment. Potential chicken litter waste from the chicken farming industry in West Sumatra is 5 tons per harvest (40 days) from a chicken livestock capacity of 100,000 chickens. This research aims to assess the potential and utilization and study the biochemistry of chicken manure waste in closed-house systems as biosorbents and fertilizers through amelioration technology. Closed-house chicken coop bedding waste (CHCCW) in the form of sawdust has functional groups such as carboxyl that can absorb cations because it can increase the negative charge in the soil so that it can be utilized by plants. In addition, the CHCCW can also absorb cations (pollutants). Chemical characteristics from the analysis results prove the ability of the CHCCW. Chicken litter waste has chemical characteristics that have the potential as a biosorbent and are valid as fertilizer, which has a proximate composition (moisture 4.26%; volatile matter 74.20%; ash 6.78% and fixed carbon 14.76%); pH (pH H2O 8.37 and pH PZC 7.37); electrical conductivity (EC) >2 dS m-1 and cation exchange capacity (CEC) 182.67 Cmol(+)kg-1. The nutrient composition of chicken manure waste in closed-house systems has macro nutrients (6.88% C; 0.06% N; 5.89% P; 34.89% K; 36.28% Ca; 5.76% S) and micronutrients (2.49% Fe; 1.39% Mn; 1.22% Zn; 1.01% Cu; and 5.15% Cl). Chicken manure waste in closed-house systems also has functional groups such as O-H, N-H, C-H, C-OH, C=C, C=O, C-O-C, Si-O, and O-CH3, which play an active role in the absorption of pollutants and nutrients in the soil. [ABSTRACT FROM AUTHOR]

In the realm of sustainable waste management, this study delves into the multifaceted potential of floral waste through its dual roles as a vermicompost and a biosorbent. As environmental challenges such as pollution and resource scarcity escalate, innovative solutions are imperative. The research meticulously explores the sustainable utilization of floral debris from diverse sources, recognizing its innate ability to serve as a biosorbent by effectively absorbing contaminants from various origins. This evaluation underscores the economic and sustainable viability of floral waste as a biosorbent, emphasizing its environmentally friendly attributes and its role in reducing soil and water pollutants. Simultaneously, the study investigates the vermicomposting process of floral waste, shedding light on the intricate microbial interactions and nutrient enrichment essential for transforming floral waste into a nutrient-rich organic fertilizer. This dual-purpose approach not only yields valuable resources for horticultural and agricultural applications but also addresses environmental issues stemming from waste management. By examining multiple sectors with promising applications for biosorbents and vermicomposts, the study underscores the versatility of this eco-friendly waste management strategy. Furthermore, it significantly contributes to the discourse on sustainable waste management by highlighting the dual environmental benefits derived from the utilization of floral waste. A comprehensive review of existing studies and practical implementations underscores the pivotal role of floral waste in achieving holistic environmental advantages. [ABSTRACT FROM AUTHOR]

The high productivity of mangosteen and its utilization in various industries produce the mangosteen peel as a waste of the process. Mangosteen peel as a lignocellulose‐based material has great potential to be utilized as a biosorbent, especially in the separation process of wastewater pollutants. Previous studies on mangosteen peel biosorbent are limited to the adsorption of heavy metal ions, dyes, and CO2 separation process. These studies show that the separation efficiency can reach above 90%, which indicates the potential to be expanded for the usage of other compounds as the adsorbate. The gradual diffusion process of adsorbate molecules into biosorbent pores depends specifically on the suitability of the materials and the operating conditions of the adsorption process. Materials suitability can be modified by the biosorbent pretreatment process to enhance its adsorption capacity. The mangosteen peel biosorbent, which still performs well in the adsorption process even after being regenerated for a few cycles, is an added value for its potential to be utilized as a biosorbent in various applications because it can reduce costs and process waste; also expand the possibility to reuse the desorbed adsorbate compound. [ABSTRACT FROM AUTHOR]

Different carbon‐based sorbents are widely used for the refinement of industrial as well as domestic effluent because of their availability, low cost, and excellent hydrophobicity. In this article, the activated biosorbent (ABs) material was prepared and applied to develop a membrane (ABs@Membrane) and sponge (ABs@Sponge) for effective oil and organic solvent cleanup from water mixtures. The one‐pot process was adopted to prepare ABs material by the simple carbonization of naturally available cotton and biowaste chitosan with sulphuric acid. The fabricated ABs@Membrane and ABs@Sponge showed excellent hydrophobicity with excellent water contact angle, i. e., 138.06° and 135.58°, respectively. Moreover, the synthesized ABs@Sponge showed excellent oil/organic solvent absorption capacity in the presence of water, i. e., 40 gm of machine oil and 62 gm of chloroform. Whereas the synthesized ABs@Membrane material showed excellent oil‐water separation efficiency (>90 %) and water flux (219.29 Lm−2 h−1) with a good oil rejection ratio (>91 %). The synthesized ABs@Membrane and ABs@Sponge material showed excellent recyclability performance up to 5th no of consecutive cycles. The straightforward synthesis and fabrication of ABs@Membrane and ABs@Sponge materials with excellent oil rejection ratio and oil/organic solvent separation performance open a new window in the effluent water treatment application. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic increased the pollution of water resources by some contaminants, e.g., chloroquine (CQN), due to its probable benefit in the treatment of the virus. Thus, is necessary the removal of CQN from water through advanced techniques. Black soybeans have been widely used due to their benefits to human health, and as a result, there was an increase in soybean husk residue, the main by-product of the soybean processing industry. Given the current scenario and the need to develop new uses for this agricultural residue, this study aimed to establish an economical and environmental biotechnology by the CQN adsorption process onto black soybean hulls (BSH) for the first time. BSH was characterized by physicochemical and spectroscopic techniques that demonstrated porosity, organic functional groups and negative surface charges. The pH study did not affect CQN adsorption pronouncedly, indicating that π-interactions and hydrogen bonds are the main mechanisms of the adsorption process. The maximum adsorption capacity was 75.06 ± 2.24 mg g−1 with 240 min of contact time at 288 K. In order to verify the biosorbent applicability, the safranin orange dye and triclosan adsorption were also evaluated onto BSH. The absorption peaks of the contaminants used in the synthetic mixture demonstrated a removal rate of 90.81 ± 0.80% for safranin orange, 66.79 ± 1.12% for triclosan and 70.62 ± 0.67% for CQN. The satisfactory removal of other contaminants indicates that BSH is a promising, affordable and environmentally friendly biosorbent with applicability potential for alternative treatment of contaminated water. [ABSTRACT FROM AUTHOR]

Recently, to protect the health of aquatic life and, indirectly, all living things, biomass-based substances have been increasingly applied as biosorbent materials to remove micropollutant agents from an aquatic environment. However, these studies are under development, and the search for more successful materials continues. Here, the biosorption of a common micropollutant, methylene blue, from an aquatic environment was investigated using the chemically activated biomass of a widely available plant species, Pyracantha coccinea M. J. Roemer. The biosorption efficiency of the biosorbent material was improved by optimizing the experimental conditions, including the contact time, micropollutant load, pH, and biosorbent material amount, and the highest performance was observed at t = 360 mins, C0 = 15 mg L−1, pH = 8 and m = 10 mg. The pseudo-second-order kinetics model and Freundlich isotherm model were in good agreement with the experimentally obtained results. The thermodynamic study suggested that the micropollutant biosorption was a favorable, spontaneous, and physical process. The micropollutant-biosorbent interaction mechanism was presented using SEM and FTIR studies. The maximum Langmuir biosorption capacity of the biosorbent was determined to be 156.674 mg g−1. The activation operation more than doubled the biosorption potential of the biosorbent material. Thus, the present study showed that the chemically activated plant biomass-based material could be a promising biosorbent for the effective removal of the micropollutant from water environment. The biosorption of a common micropollutant, methylene blue, from a water environment was studied using chemically activated biomass of Pyracantha coccinea M. J. Roemer. The activation operation more than doubled the biosorption potential of the biosorbent material. It exhibited higher micropollutant biosorption performance compared to most other biosorbents. These results indicated that the chemically activated biomaterial could be a very effective biosorbent for the micropollutant biosorption from an aqueous medium. [ABSTRACT FROM AUTHOR]

Industries play a substantial role in contaminating the freshwater sources. This study was performed to appraise the potential of biochar activated with 85% phosphoric acid was used as chemisorbent for the removal of Chromium III and VI (Cr III and VI)) and desorbed chromium was utilized for replacing the conventional basic chromium sulfate to ensure circular economy. In our previous studies, the factors for biosorption of Cr were optimized through Box–Behnken model under Response Surface Methodology. Batch adsorption studies revealed that the optimum conditions for maximum Cr (VI) biosorption by activated biochar is pH = 2, biosorbent dose: 1%, biosorbent size: 1 mm, solute concentration: 985 mg L−1 and reaction time 35 h. Based on these results a column experiments were carried out and flow rate was optimized as 0.5 ml m−1 where prominent "S" shaped breakthrough curves were noticed. The predicted values under Thomas model for the adsorption of Cr was 3827.2 µg g−1, which was in close agreement with experimental value of 3566.1 µg g−1. The percent Cr sorption varied from 70.05 to 88.75% in first cycle and showed decreasing trend in the subsequent cycles. The elutant 0.5 M H2SO4 desorbed 89.56% of chromium furthermore eluted chromium was utilized for leather tanning. Reusing of recovered chromium for tanning experiments does not alter the leather Tensile (240.82 kg cm−2) and tear strengths (32.41 kg mm−1). This study suggested that recovered chromium from biosorbent can be well utilized for leather tanning to attain the leather of equivalent qualities as that of conventional methods which could save 20–22% of the production cost besides defending the environment from Cr contamination. [ABSTRACT FROM AUTHOR]

Natural agricultural solid waste material is very cost-effective for synthesizing adsorbents utilized in the removal of heavy metal ion from economic and noneconomic wastewaters, which are numerously exploded in environmental soil and water resources. Punica granatum (pomegranate) stem powder (PGSP) was synthesized into nanoparticle size and practiced in the removal of cobalt metal ions. The adsorbent was synthesized in a greener manner in an aqueous medium. A batch adsorption study was carried out with parameters including the effect of pH (pH 4, 73.13%), adsorbent dose (200 mg, 70.80%), the concentration of metal ion (200 ppm, 81.56%) and effect of temperature (30°C, 71.56%). Characterization study of PGSP before cobalt metal ion adsorption and after cobalt metal ion adsorption was conducted, including scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy and elemental detection analysis. [ABSTRACT FROM AUTHOR]

This study aims to remove arsenic from groundwater by employing a series of batch studies on Azardicta Indica bark powder that vary in terms of physic-chemical factors such as contact time, dose, pH, initial arsenic content, and temperature. The rate of arsenic absorption decreased as it moved farther inside the biosorbent particles from its initial quick pace. At a pH of 4.0-6.0 and a dosage of 1.5 gm, the impact of contact duration on arsenic biosorption was investigated for 30 minutes. As the initial arsenic concentration rises, the proportion of arsenic biosorption decreases because mass transfer between the solute and solution interface is impeded at higher concentrations. Through the assessment of the biosorbent's mass transfer coefficients, the experimental outcomes were accurately documented in terms of Freundlich and to some degree Temkin isotherms with values of R2 0.998 and 0.956, respectively. [ABSTRACT FROM AUTHOR]

Heavy metal contamination in wastewater poses a significant threat to environmental and human health. This study investigated the potential of Chlorella sorokiana, a green alga, as a biosorbent for Cu (II) and Zn (II) removal from synthetic wastewater. Batch experiments were conducted at 28°C, pH 6, and a contact time of 60 minutes. Chlorella sorokiana displayed promising biosorption capacity, removing 85% and 75% of Cu(II) and Zn(II), respectively. Further optimization revealed enhanced removal efficiencies at pH 5 (88.5% Cu(II) and 82% Zn(II)) and a biosorbent dosage of 0.5 g/L (90.7% Cu(II) and 87.1% Zn(II)). These findings demonstrate the efficacy of Chlorella sorokiana as a biosorbent for heavy metal remediation. This research highlights the potential of biosorption as a sustainable and environmentally friendly approach for wastewater treatment, offering a promising solution for mitigating heavy metal pollution. [ABSTRACT FROM AUTHOR]

The urgent need for technological innovation to combat water pollution underscores the significance of biosorption as a potential solution. The success of biosorption hinges on the careful selection of a suitable biosorbent. Biofilms, composed of microbial communities, emerge as a promising alternative due to their expansive adsorption capacity and ready availability. In practical applications, biosorption is often executed at pollutant concentrations lethal to microbes. Consequently, comprehending the biosorption potential of biofilms with deceased microbes becomes imperative. Notably, biofilms with deceased microbes offer the added advantage of minimizing the risk of pathogenic microbial contamination. Despite this, studies are scarce comparing biosorption between intact biofilms and those with deceased microbes. This comparative analysis could enhance the feasibility of biofilms in biosorption as an eco-aquatic technology for alleviating aquatic pollution. This study aims to scrutinize the biosorption characteristics of intact biofilm (with living microbes) and autoclaved biofilm (with deceased microbes). The methods employed for analyzing biosorption characteristics encompass examining electric charge properties, FTIR spectra analysis, ion adsorption, and ion desorption. The model ions chosen for this study are K+ (monovalent ion) and Mg2+ (divalent ion). Results indicate that the biofilm's electric charge properties and adsorption capacity remain relatively unchanged post-autoclaving. Based on these findings, it can be concluded that biofilms, whether intact or autoclaved, present substantial potential as biosorbents in the advancement of eco-aquatic technology for mitigating water pollution. [ABSTRACT FROM AUTHOR]

A significant environmental concern globally is the pollution of water bodies as a result of heavy metals. To date, various attempts have been made to effectively remove heavy metals, such as those that use synthetic and biogenic materials to abate and control water pollution. The biological removal of pollutants from water is an efficient and environmentally friendly technique. In this study, we evaluated the biosorption characteristics of Zn2+ ions from aqueous solution by spent composed of raw Agaricus biosporium (RAB) and A. biosporium (SCAB). We added different biosorption doses, metal ions, and initial concentrations of pollutants to explore the adsorption of Zn2+ by RAB and SCAB. We applied pseudo-first- and second-order models to investigate the biosorption kinetics. According to our results, the rate of Zn2+ removal from the aqueous solution using raw biomass was significantly lower than that using sodium citrate-treated biomass of SCAB. When the Zn2+ concentration increased from 10 mg L−1 to 200 mg L−1, the rate of removal of RAB decreased from 73.9% to 38.4%, and that of Zn2+ by SCAB decreased from 99.9% to 75.9%. As we increased the biosorbent dose, the rate of Zn2+ removal by SCAB increased. Interestingly, Zn2 biosorption was inhibited by heavy co ions (Cu2+ and Pb2+) and light metals (e.g., Na+, Mg2+, K+, and Ca2+). When treating wastewater polluted with Zn2+, Pb2+, and Cu2+, SCAB showed good potential. The results of this study provide a scientific basis for an environmentally sound approach to controlling water pollution. [ABSTRACT FROM AUTHOR]

In this study, Aptenia cordifolia powder was utilized as a biosorbent material to effectively treat a synthetic aqueous solution polluted with methylene blue. The characterization of Aptenia cordifolia was conducted according to several analyses, including Fourier transforms infrared, scanning electron microscopy, the point of zero charge and energy dispersive X-ray. The retention process was investigated considering several factors including biosorbent mass, contact time, initial solution pH, temperature, and the initial concentration of methylene blue. The results obtained indicate that the optimal dose of adsorbent was 2 g.L-1. The equilibrium time was approximately 120 min, and the biosorption capacity of the biosorbent increases with an increase in pH. The pseudo-second-order model describes adequately the retention of methylene blue using Aptenia cordifolia. The Langmuir model proved to be more applicable in the analysis of the isotherm data, indicating a maximum retention amount of 51.82 mg.g-1. Moreover, the removal of methylene blue was thermodynamically endothermic, spontaneous, and favorable. These findings demonstrate the potential of Aptenia cordifolia biomass as an effective biosorbent for the treatment of dyes contaminated effluents. [ABSTRACT FROM AUTHOR]

Multiple contaminants are present in industrial effluents, affecting the quality of water treatment operations. As a result, understanding the outcome of the multicomponent adsorption systems is critical for developing an effective decontamination technique. In this study, a novel formulation comprising of two composites—Pennisetum glaucum (PG) biomass–functionalized carbon nanotubes (CNT), i.e., (PG + CNT), and cetyltrimethylammonium bromide (CTAB) treated Pennisetum glaucum biomass–functionalized carbon nanotubes, i.e., (PG + CNT + CTAB)—was synthesized and utilized for the adsorption of two anionic dyes, i.e., Aniline blue 93 (AB) and Congo red (CR), and two cationic dyes, Crystal violet (CV) and Malachite green (MG), from their individual and multi-adsorptive systems. The influence of different operational factors like pH, adsorbent dosage, and dye solution concentration on the adsorption process was evaluated by employing the Box-Behnken experimental design (BBD). The kinetics of AB, CR, CV, and MG biosorption were better fitted to the pseudo-2nd-order model. The unmodified and extended Langmuir models were suitable for evaluating the experimental data of individual and multicomponent systems. Meanwhile, the extended or modified Langmuir isotherm model confirmed the synergistic behavior of a single dye species over other dye species adsorption on composite surface in their respective adsorptive setups for all multicomponent systems. The thermodynamic observations indicate that the removal of cationic and anionic dyes was feasible. Overall, the synthesized composite is a biosorbent that is safe for the environment and can be used to adsorb anionic and cationic dyes from individual and multi-component dye-containing effluents at a natural pH. [ABSTRACT FROM AUTHOR]

Abstract This study aimed to assess the value of Pachira aquatica Aubl. fruit peels by exploring their applicability in the biosorption process for the removal of Ni(II) and Cd(II) metal ions. The Pachira aquatica Aubl. fruit peel biochar (PAB) was extensively characterized through various techniques, including proximate analysis, helium pycnometer, XRD, SEM, point of zero charge determination, zeta potential measurement, and Boehm titration. Subsequently, kinetic, isotherm, and thermodynamic batch biosorption studies were conducted, followed by column biosorption tests. The characteristics of PAB, including low moisture content, a neutral point of zero charge, porosity, an irregular and heterogeneous structure, a negatively charged surface, and the presence of functional groups, indicate its remarkable capacity for efficiently binding with heavy metals. Biosorption equilibrium time was achieved at 300 min for both ions, fitting well with a pseudo second-order kinetic model and Langmuir isotherm model. These data suggest that the biosorption process occurred chemically in monolayer. The column C presented an exhaust volume of 1200 mL for Ni(II) and 1080 for Cd(II) and removal of 98% and 99% of removal for Ni(II) and Cd(II), respectively. In summary, PAB demonstrates substantial potential as a biosorbent for effectively removing heavy metals, making a valuable contribution to the valorization of this co-product and the mitigation of environmental pollution.

Industrial activities generate a significant problem in the form of dye waste, which contributes to environmental pollution, particularly water pollution. Improper disposal of untreated dye waste can lead to detrimental effects on ecosystems, the environment, and living organisms. To mitigate these issues, various methods such as biological treatment, chemical oxidation, flocculation-coagulation, and adsorption are employed to remove or reduce dye and other pollutants from wastewater. Among these methods, adsorption has proven to be a cost-effective and straightforward approach for the removal of pollutants, particularly dye waste, from water. While activated carbon is commonly used as an adsorbent in the industry, it has drawbacks such as high cost and difficulty in regeneration, especially in the form of powdered activated carbon. Remazol Brilliant Blue R (RBBR) is a specific dye extensively utilized in the textile industry. It belongs to the category of reactive dyes that are challenging to degrade and pose toxicity risks to aquatic ecosystems. The use of bio-adsorbents in dye removal offers advantages such as low cost, easy availability and production, as well as the ability to be regenerated. When utilizing activated carbon derived from bio-materials, RBBR removal rates of 88.51% have been achieved. The agricultural waste powder as an adsorbent yields a removal rate of 90.82%, while non-conventional bio-adsorbents exhibit a removal rate of 90.50%. This review aims to compile information on bio-adsorbents and their effectiveness in adsorbing RBBR, shedding light on their potential for addressing dye waste pollution.

The widespread use of triclosan (TCS) across the globe poses a substantial threat to both human well-being and the ecosystem. This necessitates the development of eco-friendly adsorption techniques to address triclosan contamination in wastewater. This research aims to develop novel eco-friendly synthesis method using Syzygium jambos (SJ) leaf extract to produce small-sized Mesoporous Silica Nanoparticles (MSNs) by varying surfactant to silica ratio. Different ratios such as 1:50, 1:100, and 1:200 (1 mL of tetraethyl orthosilicate (TEOS) is equivalent to cetyltrimethylammonium bromide (CTAB) in mg) were explored without chemical stabilising agents or alcohol diluents. The synthesized materials were named as MSN1, MSN2, and MSN3. Characterisation studies using Field emission scanning electron microscopy (FE-SEM) showed that MSN3 exhibited smallest size of 30 ± 5nm. The physical, chemical and morphological properties were analysed for the materials using X-Ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), Zeta potential (ZP), Brunauer-Emmett-Teller (BET), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). Notably, the developed nanomaterial demonstrated noteworthy stability with a ZP of −33.1 mV and an impressive surface area of 545 m2/g. FT-IR peaks of biosorbent were obtained at 460, 800, and 975 1/cm. This confirms the existence of (Si–O–Si) bonds. The XRD results reveals that it possess amorphous nature of silica without any impurities. N2 adsorption-desorption studies yielded a pore radius of 16.8 Å and volume of pores are 0.890 cc/g indicating its potential as an adsorbent and its utility for material functionalisation. The developed biosorbent exhibited enhanced adsorption properties for removal of triclosan from synthetic wastewater with 76 % removal at 0.5g/L dose of adsorbent.

Methylene blue (industrial dye) presents adverse effects on the environment. Traditionally, this dye is removed by adsorption with commercial activated carbon. Researchers are exploring low-cost alternatives using agro-industrial waste. This study evaluates Chandler-type walnut shells for removing methylene blue from aqueous solution. Batch experiments with two nominal sizes reveal that pseudo-second-order kinetics best describe adsorption. Langmuir isotherms show adsorption capacities of 8.636 and 38.46 mg g−1 for analyzed sizes. The best removal capacity (97%) was observed for smaller particle sizes (2.36–1.18 to 1.18–0.6 mm) with an initial concentration of 200 mg L−1. High initial concentrations decrease removal due to porous saturation. The best removal capacity in continuous systems is 50.47 mg g−1, with a saturation time of 8 hours at 5 cm bed height, adsorbent size 1.18–0.6 mm, 60 mg L−1 initial concentration, and 15 mL min−1 flow rate. The Thomas model best fits the data, suggesting external mass transfer and intra-particle diffusion. This study provides crucial insights for scaling processes and shows a competitive removal efficiency of methylene blue using walnut shells compared to other biosorbents. Further investigation is needed to analyze channeling phenomena observed with increased bed heights in continuous systems.

This study aimed to assess the value of Pachira aquatica Aubl. fruit peels by exploring their applicability in the biosorption process for the removal of Ni(II) and Cd(II) metal ions. The Pachira aquatica Aubl. fruit peel biochar (PAB) was extensively characterized through various techniques, including proximate analysis, helium pycnometer, XRD, SEM, point of zero charge determination, zeta potential measurement, and Boehm titration. Subsequently, kinetic, isotherm, and thermodynamic batch biosorption studies were conducted, followed by column biosorption tests. The characteristics of PAB, including low moisture content, a neutral point of zero charge, porosity, an irregular and heterogeneous structure, a negatively charged surface, and the presence of functional groups, indicate its remarkable capacity for efficiently binding with heavy metals. Biosorption equilibrium time was achieved at 300 min for both ions, fitting well with a pseudo second-order kinetic model and Langmuir isotherm model. These data suggest that the biosorption process occurred chemically in monolayer. The column C presented an exhaust volume of 1200 mL for Ni(II) and 1080 for Cd(II) and removal of 98% and 99% of removal for Ni(II) and Cd(II), respectively. In summary, PAB demonstrates substantial potential as a biosorbent for effectively removing heavy metals, making a valuable contribution to the valorization of this co-product and the mitigation of environmental pollution. [ABSTRACT FROM AUTHOR]

The textile industry in the world keeps increasing, but it harms environmental pollution caused by textile dye waste. Synthetic dyes contain carcinogenic and mutagenic ingredients that can demage the environment and aquatic biota. The alternative to handling dye pollution with a low-cost method is adsorption using nitric acid-activated coconut fiber. Coconut fiber was an abundant agricultural waste and economical, and it had an active site that contained many compounds such as cellulose, lignin, pyroligneous acid, and tannin molecules. This study used the UV-Vis Spectrophotometer analysis method to determine the effect of pH, contact time, and coconut fiber on the adsorption capacity of methylene blue. The result showed that the optimal conditions for adsorption were a pH of 5, a contact time of 75 minutes, and a percentage adsorption of the variation of contact time of 99.628%. The adsorption study was according to a pseudo-second-order reaction with a constant reaction rate of 0.050 g mg-1 minute-1. The maximum adsorption capacity was 2 mg g-1, with the percentage of methylene blue adsorbed at 99.84%. Adsorption occurs chemically with an energy of 35.4 kJ mol-1, so it can be determined that it occurs with a monolayer mechanism. [ABSTRACT FROM AUTHOR]

Natural adsorbents offer promise for application in environmental protection mainly based on the cost efficiency and biodegradable nature. In the current work, a biosorbent has been synthesized from coconut shell (a common agrochemical waste) in the presence of ultrasound with an objective to improve the microstructure of the carbon coupled with activation using mixture of HNO3 with H2SO4 (7:3 proportion). SEM analysis clearly confirmed that ultrasound induced cavitational effects improved the porous structure of the sample. FTIR and XRD results confirmed the favorable adsorption characteristics for the synthesized activated carbon with no negative changes due to the use of ultrasound. The synthesized adsorbent was used for the removal of a toxic dye, Rhodamine 6G present in effluent at a level of 25 mg L−1. The detailed study into effect of operating parameters elucidated that optimum treatment time for maximum dye removal was 22 min whereas the optimal value of biosorbent loading and pH were 8 gL−1 and 10, respectively. The equilibrium data was fitted into different types of adsorption isotherm models, and Langmuir isotherm model was elucidated as the best fitted model with an adsorption capacity of 90.9 mg g−1. Similarly, the kinetic studies revealed that pseudo second order model fitted better than all the other models. Overall, the efficacy of prepared adsorbent in the presence of ultrasound was effectively demonstrated for the Rhodamine 6G removal from wastewater, also demonstrating the effect of different operating conditions during the adsorption. [ABSTRACT FROM AUTHOR]

The presence of micropollutants, such as caffeine (CAF), has been detected throughout the world, since conventional treatment plants are not able to properly degrade them. CAF is a widely consumed stimulant, and has been demanding the development of efficient methodologies for its removal. Aiming at the agriculture waste valorization, a new hydrochar was developed based on chemical and thermal modification of peach stones (mod-PS) for CAF removal from water and from a synthetic mixture. The morphology, functional groups and surface electrical charge of the adsorbent were characterized by SEM, FTIR and zeta potential, respectively. Regarding CAF adsorption performance, the equilibrium time was reached at 480 min and the pseudo-second-order model presented the best fit for the experimental data. The maximum adsorption capacity was 68.39 mg g-1 (298 K) and the Langmuir model exhibited a better fit for the isothermal data. The thermodynamic properties confirmed that the process was exothermic, spontaneous and reversible. The main adsorption mechanisms were hydrogen bonds and π-interactions. The global removal efficiency was satisfactory in the synthetic mixture simulating real wastewater (67%). Therefore, the proposed new hydrochar has potential application as a low-cost adsorbent for CAF removal. [ABSTRACT FROM AUTHOR]

Olive tree pruning waste, mainly composed of olive branches, was converted into a value-added and sustainable product capable of lithium as a biosorbent through alkali treatment and phosphorylation reaction. Characterization studies were performed by SEM–EDX, XPS, FTIR, and TGA. Factors affecting biosorption mechanism, i.e., sorbent dosage, pH, initial Li+ concentration and temperature, and competitive ions' presence, were investigated the synthesized functionalized olive branches (FOB). A commercial lithium selective resin, Lewatit TP 260, was also compared with FOB in batch and column studies. The Freundlich model fits adsorption isotherms better than the Langmuir model, with a maximum adsorption capacity of 6.7 mg/g at 30 °C and pH 7–8. Kinetic studies proved fast kinetics and equilibrium were attained in 6 min, while thermodynamic studies showed an exothermic Δ H o = - 17.52 k J / m o l , spontaneous reaction Δ G o < 0 at all temperatures), and increased randomness Δ S o = + 24.27 J / m o l. K ) at the interaction interface. Column studies revealed that although Lewatit TP 260 resin showed higher sorption capacity, its desorption efficiency (50.42%) was lower than that of FOB (99.9%), and the degree of column utilization of FOB (56.81%) was better than Lewatit TP 260 resin's (16.0%). The findings were encouraging in the successful synthesis of a promising biosorbent from an abundant waste in Turkey for use in sustainable lithium recovery from aqueous sources. [ABSTRACT FROM AUTHOR]

Heavy metals are the main pollutants in water and are an important global problem that threatens human health and ecosystems. In recent years, there has been an increasing interest in the use of genetically modified bacteria as an eco‐friendly method to solve heavy metal pollution problems. The goal of this study was to generate genetically modified Escherichia coli expressing human metallothioneins (hMT2A and hMT3) and to determine their tolerance, bioaccumulation, and biosorption capacity to lead (Pb2+). Recombinant MT2A and MT3 strains expressing MT were successfully generated. Minimum inhibition concentrations (MIC) of Pb for MT2A and MT3 were found to be 1750 and 2000 mg L−1, respectively. Pb2+ resistance and bioaccumulation capacity of MT3 were higher than MT2A. Therefore, only MT3 biosorbent was used in Pb2+ biosorption, and its efficiency was examined by performing experiments in a batch system. Pb2+ biosorption by MT3 was evaluated in terms of isotherms, kinetics, and thermodynamics. The results showed that Pb biosorption fits to the Langmuir isotherm model and the pseudo‐first‐order kinetic model, and the reaction is exothermic. The maximum Pb2+ capacity of the biosorbent was 50 mg Pb2+g−1. The potential of MT3 in Pb biosorption was characterized by Fourier‐transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM) analyses. The desorption study showed that the sorbent had up to 74% recovery and could be effectively used four times. These findings imply that this biosorbent can be applied as a promising, precise, and effective means of removing Pb2+ from contaminated waters. Practitioner Points: In this study, the tolerance levels, bioaccumulation, and biosorption capacities of Pb in aqueous solutions were determined for the first time in recombinant MT2A and MT3 strains in which human MT2A and MT3 genes were cloned.The biosorbent of MT3, which was determined to be more effective in Pb bioaccumulation, was synthesized and used in Pb biosorption.The Pb biosorption mechanism of MT3 biosorbent was identified using isotherm modeling, kinetic modeling, and thermodynamic studies.The maximum Pb removal percentage capacity of the biosorbent was 90%, whereas the maximum biosorption capacity was up to 50 mg Pb2+g−1.These results indicated that MT3 biosorbent has a higher Pb biosorption capacity than existing recombinant biosorbents. MT3 biosorbent can be used as a promising and effective biosorbent for removing Pb from wastewater. [ABSTRACT FROM AUTHOR]

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Methyl orange, an anionic dye, is injurious to health and the environment which must be treated before discharging. The processed fish (Labeo rohita) scales were characterized by scanning electron microscope (SEM), the attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FT-IR), and BET surface area analyzer. The BET surface area and pore diameter were observed to be 192 m2 g−1 and 44 nm, respectively. Influences of parameters such as pH, temperature, and concentration of adsorbent were studied by response surface methodology and analysis of variance (ANOVA) to optimize methyl orange dye uptake in adsorption process by fish scale. The influences of factors on adsorption capacity followed the order (initial concentration ˃ temperature ˃ pH). The fish scale attained a high sorption capacity (Langmuir capacity of 520 mg g−1 at pH 5.3, 283 K) towards methyl orange. The thermodynamics analyses implied that the physisorption was an exothermic and spontaneous process (ΔG0 = negative, ΔH0 = −9.17 kJ mol−1 and ΔS0 = + 0.03 J mol−1 K−1). The interaction of fish scale biosorbent with methyl orange dye was also explored with the assistance of a mechanistic pathway. The results indicate that the fish scale could be employed as an effective biosorbent for the removal of methyl orange dye from aqueous solution. [ABSTRACT FROM AUTHOR]

In this study, sage, chamomile, and tarragon leaves, which are used as spices and consumed as beverages in daily life, were considered as different biosorbents that can be used in water purification by biosorption. At the same time, the effects of the parameters of initial dye concentration (10-200 mg/L), temperature (20-50 °C) and contact time (0-120 min) on biosorption capacity were investigated. The biosorption processes were found to follow Freundlich isotherm and pseudo-second order (PSO) reaction kinetics. In the study, the process was also modeled using multi-tree evolutionary computation based automatic programming (AP) methods. The methods used initial dye concentration, temperature, and contact time as variables. According to the simulation results, these methods obtained nonlinear mathematical models of the processes with R² values as high as 0.99 for each biosorbent. By providing the most accurate models to accurately predict biosorption capacity, this study will make a significant contribution to the field of water treatment using experimental and AP methods. [ABSTRACT FROM AUTHOR]

Heavy metal contamination in wastewater poses a significant threat to environmental and human health. This study investigated the potential of Chlorella sorokiana, a green alga, as a biosorbent for Cu (II) and Zn (II) removal from synthetic wastewater. Batch experiments were conducted at 28°C, pH 6, and a contact time of 60 minutes. Chlorella sorokiana displayed promising biosorption capacity, removing 85% and 75% of Cu (II) and Zn (II), respectively. Further optimization revealed enhanced removal efficiencies at pH 5 (88.5% Cu (II) and 82% Zn (II)) and a biosorbent dosage of 0.5 g/L (90.7% Cu (II) and 87.1% Zn (II)). These findings demonstrate the efficacy of Chlorella sorokiana as a biosorbent for heavy metal remediation. This research highlights the potential of biosorption as a sustainable and environmentally friendly approach for wastewater treatment, offering a promising solution for mitigating heavy metal pollution.

Chitosan (CS) is widely used in the treatment of wastewater containing metal ions. However, the poor stability in acidic aqueous solutions severely limits its application in many practical scenarios. In this work, a CS-based composite nanofiber membrane was prepared by electrospinning using urushiol, a natural biomaterial, as the cross-linking agent. The application of the CS-urushiol (CS-U) membrane in the adsorption and recovery of Cr(vi) in wastewater was systematically studied. The CS-U membrane showed great resistance to strongly acidic and oxidative environments, and the adsorption process combined two mechanisms of electrostatic attraction and redox reaction. Due to the nanoscale fibers, porous structure, and strong acid resistance, the CS-U membrane adsorbed Cr(vi) rapidly and efficiently in both batch and continuous modes. Moreover, the adsorption capacity and selectivity of the CS-U membrane for Cr(vi) could be maximized simultaneously by adjusting the solution pH, promoting the recovery of high-purity Cr2O3.