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Most undeveloped and developing countries have adopted landfill as the ultimate disposal method for their Municipal Solid Waste (MSW). Leachate produced by a landfill site is highly dangerous, with high concentrations of organic and inorganic pollutants, ammonia and toxic heavy metals. Heavy metals commonly found in landfill leachate are copper, lead, mercury, cadmium, arsenic etc., The main objective of this research is to study the removal of heavy metals copper and lead, from synthetic leachate using TiO2 and Ag-doped TiO2 nanomaterials by a heterogeneous photocatalytic process. The photocatalytic experiments were conducted using a compound parabolic collector in sunlight. The design of experiment is used to obtain the minimum number of experiments for the study, to analyze the data and to understand the interaction between the process variables and their responses. Photocatalytic behavior of copper and lead removal has been demonstrated using an Artificial Neural Network (ANN) model. Characterization studies are conducted on TiO2 and Ag-doped TiO2 nanomaterials by XRD, SEM and EDX. At optimum parameters of the dosage 0.75 g/L, pH 5 and irradiation time of 100 min, copper removal from synthetic leachate was found to be 80.38% and 80.12%, lead removal efficiency was 97.2% and 96.34% for TiO2 and Ag-doped TiO2, respectively. The determination coefficient value obtained by RSM and ANN ensures that the developed model of copper and lead removal gives an accurate prediction. The kinetic study shows that, copper and lead removal by photocatalytic process are described well by a Langmuir–Hinshelwood kinetic model. [ABSTRACT FROM AUTHOR]

Synthetic textile dye malachite green (MG) and heavy metals present in industrial wastewater are hazardous to the ecosystem. Bioremediation of dyes and heavy metals using dry-biomasses has advantages over chemical methods. This study screened an acclimatized, heavy metal-resistant, and dye-degrading Gram positive Bacillus licheniformis AG3 strain from the textile wastewater near Kolkata, West Bengal. The EDXRF analysis of this colored wastewater effluent showed 36.33 mg/L lead, significantly higher than the WHO recommendation. Previously, Bag et al. showed bioremediation of synthetic dyes using dry-biomass of Bacillus cereus M116 from an aqueous solution (Bag et al. Arch Microbiol 203(7):3811–3823, 2021). Here, a consortium of dry-biomasses of B.licheniformis AG3 and B. cereus M116 strains (1:1 w/w ratio) was prepared for the simultaneous removal of lead and MG from wastewater. Statistical optimization determines that the pH, initial concentration of contaminants, and dry-biomass concentrations are critical for bioremediation under batch procedures. Further, optimization using the response surface methodology showed that 0.01% consortium dry-biomasses eliminated a maximum of 99.35% MG and 96.01% lead (II) within 6 h. SEM–EDS and FTIR confirmed a strong surface biosorption. Furthermore, a fixed-bed biofilter column of the consortium dry-biomasses was prepared, which was able to remove 98.1% MG and 98.5% lead at the 0.5–1 mL/min flow rate. Together, this study developed a biofilter with a consortium dry biomasses of B. licheniformis AG3 and B. cereus M116 for the simultaneous removal of MG and lead from wastewater. [ABSTRACT FROM AUTHOR]

Synthetic textile dye malachite green (MG) and heavy metals present in industrial wastewater are hazardous to the ecosystem. Bioremediation of dyes and heavy metals using dry-biomasses has advantages over chemical methods. This study screened an acclimatized, heavy metal-resistant, and dye-degrading Gram positive Bacillus licheniformis AG3 strain from the textile wastewater near Kolkata, West Bengal. The EDXRF analysis of this colored wastewater effluent showed 36.33 mg/L lead, significantly higher than the WHO recommendation. Previously, Bag et al. showed bioremediation of synthetic dyes using dry-biomass of Bacillus cereus M116 from an aqueous solution (Bag et al. Arch Microbiol 203(7):3811–3823, 2021). Here, a consortium of dry-biomasses of B.licheniformis AG3 and B. cereus M116 strains (1:1 w/w ratio) was prepared for the simultaneous removal of lead and MG from wastewater. Statistical optimization determines that the pH, initial concentration of contaminants, and dry-biomass concentrations are critical for bioremediation under batch procedures. Further, optimization using the response surface methodology showed that 0.01% consortium dry-biomasses eliminated a maximum of 99.35% MG and 96.01% lead (II) within 6 h. SEM–EDS and FTIR confirmed a strong surface biosorption. Furthermore, a fixed-bed biofilter column of the consortium dry-biomasses was prepared, which was able to remove 98.1% MG and 98.5% lead at the 0.5–1 mL/min flow rate. Together, this study developed a biofilter with a consortium dry biomasses of B. licheniformis AG3 and B. cereus M116 for the simultaneous removal of MG and lead from wastewater. [ABSTRACT FROM AUTHOR]

One interesting method for environmental remediation is the use of ZnO/ZrO2 composites in the photocatalytic degradation of lead (Pb) in wastewater. Several studies have investigated different types of composites for the removal of heavy metals from wastewater. However, the efficiency of these composites in removing the heavy metals remains debatable. Hence, this study investigated the potential of using a ZnO/ZrO2 composite for the removal of Pb from wastewater. Response surface methodology (RSM) was utilized in this work to maximize the Pb photocatalytic removal over ZnO/ZrO2 in simulated wastewater. Based on a central composite design (CCD), the experimental design included adjusting critical process parameters such as catalyst dosage, initial Pb concentration, and pH. The ZnO/ZrO2 composite was synthesized using a physical mixing technique, and its physicochemical properties were studied by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infra-red (FTIR), and X-ray diffraction (XRD). Under visible light irradiation, photocatalytic Pb removal tests were carried out in a batch reactor. The findings showed that a ZnO/ZrO2 dose of 100 mg/L, a pH of 10, and an initial Pb content of 15 ppm were the optimal conditions for maximal Pb removal (above 91.2%). The actual Pb removal obtained from the experimental runs was highly correlated with that predicted using the RSM quadratic model. The usefulness of ZnO/ZrO2 composites for photocatalytic Pb removal is demonstrated in this work, which also emphasizes the significance of RSM in process parameter optimization for improved pollutant degradation. The models that have been proposed offer significant perspectives for the development and scalability of effective photocatalytic systems intended to remove heavy metals from wastewater. [ABSTRACT FROM AUTHOR]

Industrial effluents pose a serious environmental problem, because they contain toxic contaminants mainly heavy metals that are the most dangerous to humans, animals, plants, and the environment in general. Phytoremediation using macrophytes is an adopted technique for the environment decontamination due to its efficiency and cost-effectiveness. The present study aims to highlight the capabilities of macrophytes to remove heavy metals from wastewater of Biskra region (Algeria). The methodology consists of filling out the filters planted with Arundo donax and Phragmites australis with raw industrial wastewater, then recovering decontaminated water after 15 days to assess removal of lead, copper, zinc, and iron. Both plants had shown a good efficiency for the removal of metals loaded in wastewater eliminating about 94 to 98% of initial concentration. In addition, calculated bioaccumulation factor (BAF) had confirmed the accumulation of heavy metals in different parts of experimental plants; recorded values of BAF > 1 allowed the consideration of Arundo donax and Phragmites australis as good hyper-accumulator plants. Obtained results confirm the efficiency of phytoremediation technology using macrophytes for the wastewater treatment in particular and the environment decontamination in general. [ABSTRACT FROM AUTHOR]

Lead and nitrate are pollutants that are commonly found in wastewater, and these pollutants pose significant risks to humans, animals, plants, and the environment. Therefore, it is essential to treat the wastewater to remove these toxic substances. This study utilized hydroxide precipitation for the removal of lead and nitrate from simulated lead- and nitrate-containing wastewater through jar testing. The effects of pH, lead nitrate (Pb(NO3)2) concentration, and precipitant-to-metal ([P]/[M]) ratio were examined. The hydroxide precipitation effectively removed lead and nitrate by forming basic lead nitrate precipitates, such as lead hydroxide nitrates and lead oxide hydroxide nitrates, and operated efficiently at a pH of around 8.0. Lead and nitrate removal was highly effective and primarily influenced by the [P]/[M] ratio, with [P]/[M] of 1.0 as the optimum condition. Varying the lead nitrate concentrations resulted in a higher sludge volume compared to other parameters; however, it was only significant in nitrate removal with an optimum concentration of 0.07 M. [ABSTRACT FROM AUTHOR]

Synthesis of a magnetite nanoadsorbent was reported in the study. In this regard, poly(amidoamine) (PAMAM) dendrimer (with generation 10)-functionalized Fe3O4@SiO2/APTES ((3-aminopropyl) triethoxysilane) was prepared, modified by benzaldehyde (BZ), and characterized by fourier-transfer-infrared (FTIR), vibrating-sample-magnetometer (VSM), field-emission-scanning-electron-microscope (FE-SEM), X-Ray-diffraction (XRD), thermal-gravimetric-analysis (TGA), and elemental analysis. The nanoadsorbent with VSM value of 35.3 emu/g was used to investigate adsorption of Pb(II) ions from aqueous solutions and this process relied on the solution pH, lead concentration, nanoadsorbent dose, contact time, and temperature. The results revealed the maximum adsorption efficiency of 97.56% in pH = 6, initial lead concentration = 160 mg L−1, adsorbent dose of 15 mg, contact time = 60 min, and temperature = 45 °C. The adsorption isotherm and kinetic models of Pb(II) removal followed the Freundlich model and pseudo-second-order, respectively. The adsorption was endothermic and spontaneous, which was exhibited by the thermodynamic parameters. This research suggests that the nanoadsorbent can be considered for the other metal ions removal from wastewater treatment. [ABSTRACT FROM AUTHOR]

In this study, dead Bacillus niacini microorganisms were used to support the immobilization of magnetic iron nanoparticles, creating a magnetic nano-biosorbent for wastewater treatment through magnetic separation. Magnetic nano-biosorbent was characterized via scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectrophotometry, Brunauer–Emmett–Teller analysis, and vibration sample magnetometry techniques. The laser particle sizer confirmed a uniform distribution in the particle agglomerate sizes of magnetic iron nanoparticles and magnetic nano-biosorbent, affirming successful composite formation. Energy-dispersive X-ray spectroscopy confirmed Bacillus niacini specific elements, and Fourier transform infrared spectrophotometry indicated effective Bacillus niacini coating onto magnetic iron nanoparticles. Magnetic nano-biosorbent's efficacy for toluidine blue and lead (II) removal, considering pH, contact time, magnetic nano-biosorbent dosage, and initial pollutant concentrations, was assessed. Langmuir isotherms described toluidine blue and lead (II) biosorption optimally. Kinetic data matched the pseudo-first-order and pseudo-second-order models, implying multiple biosorption mechanisms. Magnetic nano-biosorbent displayed a biosorption capacity of 66.52 ± 0.68 mg/g for lead (II) and 82.88 ± 0.79 mg/g for toluidine blue. Reusability tests showed effective reuse for up to five cycles. The magnetic nano-biosorbent presents significant potential for wastewater treatment due to its high biosorption capacity, efficient removal, and cost-effective synthesis. [ABSTRACT FROM AUTHOR]

This study focuses on the improvement of bioremediation of textile dye Reactive Red 195 using agro-industrial waste, groundnut oil cake (GNOC) obtained after oil-pressing. The treatment of GNOC with 1 N H2SO4 had resulted in physiochemical changes on the insoluble porous adsorbent, which improved their adsorption efficiency. The dye removal efficiency increased from 55% to 94% on acidification of GNOC. The raw groundnut oil cake (RGNOC) and acid-treated groundnut oil cake (AGNOC) were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction, and zeta potential. The rate and efficiency of dye adsorption were examined using adsorption kinetics and isotherm models. The results confirm that acid-treated GNOC eliminates impurities, alter the surface functional groups, and significantly increase porous surface areas of RGNOC. The investigation of key factors such as contact time, initial concentration of dye, static/agitation impact, particle size, and adsorbent dose had significantly influenced adsorption capacity of GNOC. Adsorption of dye fits best into the Langmuir model and equilibrium data of dye on AGNOC was explained by psuedo-second-order reaction with maximum adsorption capacity of 12.65 mg/g. This emphasis AGNOC has a very excellent potential to remove the textile dye Reactive Red dye from industrial effluent. This study reports the primary investigation exploring the application of groundnut oil cake (RGNOC) and its acid-modified (AGNOC) version for the bioremediation of industrially used textile dye Reactive Red 195 (RR195). The core objective of this study is to use a low-cost biosorbent to remove RR195 dye from effluent that pose risk to the health and environment. This study analyses the adsorption capacity of RGNOC and its acid-modified version AGNOC to treat contaminated water and the influencing parameters. AGNOC adsorption potential for RR195 dye sequestration was shown to be higher compared to RGNOC. Acidification of the adsorbent is simple, cost expensive, and more efficient alternate approaches to scale up for industrial application. As a result, an attempt has been made to add a new adsorbent to the database. [ABSTRACT FROM AUTHOR]

The present study performed synthesis and characterization nanocomposite based polysaccharide Chitosan/Agar and Chitosan/Agar/SiO2 nanoparticles as adsorbents for remove amoxicillin and naproxen as the pharmaceuticals from an aqueous solution. The structure and morphology of nanocomposite were investigated using X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDX), Fourier‐transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Field Emission Scanning Electron Microscopes (FE‐SEM) and Dynamic light scattering (DLS). The removal performance of the Chitosan/Agar and Chitosan/Agar/SiO2 nanoparticles nanocomposite as adsorbent for removing amoxicillin and naproxen as sample of pharmaceutical industry effluents in aqueous solutions was investigated under different influence factors, including contact time, initial concentration, pH conditions and temperature. The maximum adsorption removal for amoxicillin with Agar/Chitosan and Agar/Chitosan/SiO2 nanocomposite at initial concentrations of 20 mg/l was 97.85 % and 87.9 %, respectively. With increasing temperature from 10 to 30°C, the removal efficiency for naproxen for both adsorbents is 99 %. The prepared nanocomposites showed good performance in adsorbing naproxen and amoxicillin. The maximum adsorption efficiency of nanocomposite was 99 % and 91 % for naproxen and amoxicillin, respectively. The optimum condition for pharmaceuticals removal by the nanocomposite was initial concentration: 20 mg/l, adsorbent dose: 0.05 g, contact time: 10 min, and pH=6. [ABSTRACT FROM AUTHOR]

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]

Heavy metals exist in the ecosystem both naturally and due to anthropogenic activities and as recalcitrant pollutants; they are non-biodegradable and cause acute and chronic diseases to human beings and many lifeforms. A statistical experimental approach was applied in this current study to optimize the detoxification of mercury [Hg(II)] from mono-component biosorption system by a novel hybrid granular activated carbon (biosorbent) prepared from maize plant residues. The analysis of variance by the application of central composite design shows that all the studied independent factors greatly influence Hg(II) removal efficiency and uptake capacity. The optimum experimental condition of 30 min contact time, 0.5 g/L biosorbent dosage, and 15 mg/L initial Hg(II) concentration were achieved after seeking 20 optimization solutions at 0.903 desirability. The optimum percentage removal and uptake capacity of Hg(II) at the optimal experimental setup was 96.7% and 10.8 mg/g, respectively. To confirm the quadratic models developed for the prediction of the responses as a function of the independent factors, confirmatory laboratory experiments were performed at the optimum condition. The results show that at the established best experimental condition, the optimum Hg(II) removal efficiency of 98.3% and uptake capacity of 11.2 mg/g were attained, which were within the prediction intervals indicating the suitability of the quadratic models in predicting future cases. The TEM and XRD analyses show that the Hg(II) ions were adsorbed by the biosorbent successfully and this suggests the potential and applicability of this novel biosorbent in treating water contaminants, especially heavy metals. [ABSTRACT FROM AUTHOR]

The discharge of lead and cadmium wastewater, along with the pollution caused by phosphogypsum, represents a particularly urgent environmental issue. This study employed a straightforward hydrothermal method to convert phosphogypsum into porous calcium silicate hydrate (P-CSH), which was then used to remove and recover Pb(II) and Cd(II) from wastewater. The adsorption capacities of P-CSH for Pb(II) and Cd(II) were notably high at 989.3 mg/g and 290.3 mg/g, respectively. The adsorption processes adhered to the pseudo-second-order kinetics model and the Langmuir isotherm model. Due to identical adsorption sites on P-CSH for both Pb(II) and Cd(II), competitive interaction occurred when both ions were present simultaneously. Additionally, the adsorption efficacy was minimally impacted by the presence of common coexisting cations in wastewater. The dominant mechanisms for removing Pb(II) and Cd(II) via P-CSH were chemical precipitation and surface complexation. Moreover, the adsorbed heavy metals were efficiently separated and reclaimed from the wastewater through a stepwise desorption process. The primary components of the residue from stepwise desorption were quartz and amorphous SiO2. Following dissolution via pressurized alkaline leaching, this residue could be recycled for synthesizing P-CSH. This research offered a new strategy for the resourceful use of phosphogypsum and heavy metal wastewater. [ABSTRACT FROM AUTHOR]

The aim of the present study was to compare the effectiveness of raw chicken feathers (RCFs), NaOH and ethylenediamine-modified chicken feathers (MCFs), and xanthate-modified chicken feathers (XMCFs), treated with both NaOH, ethylenediamine, and carbon disulfide. The physicochemical characteristics of the biosorbents were analyzed using attenuated total reflection Fourier transform infrared spectrophotometry (ATR-FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), adsorption of N2 at −196°C and point of zero charge determination (pHpzc). The biosorption of Cr(VI) using MCFs and XMCFs was evaluated through various parameters, namely, pH, biosorbent amount, and contact time in batch experiments. The results showed a significant increase in the biosorption capacities of MCFs (90.90 mg/g) and XMCFs (100 mg/g) compared to RCFs (52.63 mg/g). The batch adsorption experiments indicated that the optimal conditions for biosorption were pH 2.0, with an equilibrium contact time of 90 min for RCFs, and 60 min for both MCFs and XMCFs. The optimal biosorbent concentrations were 16 g L−1 for RCFs and 12 g L−1 for both MCFs and XMCFs. The biosorption behavior was well described by the Langmuir isotherm and pseudo-second-order kinetic models. The thermodynamic parameters indicated that the biosorption of Cr(VI) onto the biosorbents was a spontaneous and endothermic process. Desorption analysis was carried out using a 0.1 M NaOH solution. [ABSTRACT FROM AUTHOR]

Heavy metal contamination in wastewater has been an issue for the environment and human health nowadays. If these wastewaters are exposed directly to the environment, it will be hazardous for the environment and personal health. So, it is very necessary to treat these ground and surface wastewater before exposing into environment. For this, an effective technique were developed which removed heavy metals from wastewater easily, economically and effectively. The cellulose nano-crystals (CNC) were isolated from banana rachis fibres by a series of chemical treatments as well as 50% H2SO4 hydrolysis successively. On the other hand, raw Indonesian type's bituminous coal was collected from Noapara industrial area, Jashore, Khulna and was pyrolysed at 700°C, activated by 2M HCl at 700°C and also carbonised at 500°C followed by activation with 30% H3PO4 acid. In this process, adsorbent of modified charcoal-CNC composites was used for the removal of methyl orange dye and five heavy metals, such as Ni(II), Pb(II), Cr(III), Cd(II) and Co(II)), from wastewater and the uptake capacity, selectivity and removal efficiency were also discussed. The filtering efficiency of wastewater purifications were characterised by FTIR, X-RD, TGA, SEM analysis. Finally, wastewater solution and the filtrates solutions were characterised by UV-Vis, and AAS techniques. [ABSTRACT FROM AUTHOR]

Industrialization has caused serious heavy metal pollution in water resources, which is harmful to human health. It is of great significance to use heavy metal removal technology to ensure water safety. In this study, a new kaolin/chitosan composite (TGL-CS) was prepared for the adsorption of lead-containing wastewater based on the mercapto-alkenyl base reaction strategy. The effects of pH, adsorbent dosage and ionic strength on the adsorption performance of TGL-CS were investigated. The adsorption process of Pb(II) on TGL-CS is consistent with the Langmuir isotherm and pseudo-second-order kinetic model. The maximum adsorption capacity of TGL-CS for Pb(II) was 87.72 mg/g. The adsorption mechanism of TGL-CS is mainly the coordination between Pb(II) and hydroxyl, amino and sulfur-containing groups. In particular, the click chemical reaction does not consume the amino group in chitosan but also introduces the sulfur-containing group to improve the adsorption capacity of heavy metals. In addition, the ionic strength in the environment system has little effect on the adsorption of Pb(II) by TGL-CS, and the reusability of TGL-CS is high. In summary, TGL-CS has the advantages of low cost, simple preparation, and broad application prospects in the treatment of heavy metal-polluted water bodies. [ABSTRACT FROM AUTHOR]

Various wastes can be utilized to produce activated carbon, one of the wastes that can be utilized is nutmeg shell (Myristica fragrans). Activated carbon from nutmeg shells (Myristica fragrans) was used in this study to reduce the content of Pb(II) and Cu(II) ions in liquid waste. This research utilized the adsorption method with the batch system to determine the optimum contact time, optimum pH, and adsorption capacity. The characterization of activated carbon was done by Scanning Electron Microscopy (SEM) and Surface Area Analyzers (SAA). The content of Pb(II) and Cu(II) ions in the filtrate after adsorption was analyzed using an atomic absorption spectrophotometer (AAS). The results of SEM analysis showed that the carbon surface was cleaner and had more open pores after the activation process than before activation. The carbon surface area is 19.6243 m².g-1. From the results of AAS analysis, the optimum time and pH for Pb(II) and Cu(II) ions was 40 min at pH 5 and 70 min at pH 4. With the Freundlich isotherm method, the adsorption capacity of the adsorbent for Pb(II) ions was 9.6028 mg.g-1 and Cu(II) ions was 0.035 mg.g-1, and the adsorption effectiveness on liquid waste for Pb and Cu metals was 1.9454 mg.g-1 and 0.4251 mg.g-1, respectively. The results showed that activated carbon from the nutmeg shell (Myristica fragrans) was able to reduce the levels of Pb(II) and Cu(II) ions in liquid waste. [ABSTRACT FROM AUTHOR]

Removal of dissolved zinc (Zn) from water by a novel alkali-activated material (AAM) prepared from steel industry slags in a fixed-bed column was investigated. Design of experiments was used to find the optimum operation parameters [flow rate $\lpar Q\rpar$ (Q) , adsorbent mass, ($m_{{\rm ads}}$ m ads ), and initial Zn concentration ($C_0$ C 0 )] for the removal of Zn2+ from a ZnCl2 solution. Regression models for the breakthrough ($q_{\rm b}$ q b ), and saturation ($q_{{\rm sat}}$ q sat ) capacities of the bed and three other response parameters as functions of $Q$ Q , $m_{{\rm ads}}$ m ads and $C_0$ C 0 were fitted with coefficients of determination ($R^2$ R 2 ) ranging from 0.48 to 0.99. Experimental values of $q_{\rm b}$ q b and $q_{{\rm sat}}$ q sat varied within 1.42–7.03 mg Zn/g and 10.57–17.25 mg Zn/g, respectively. The optimum operation parameters were determined to be $Q =$ Q = 1.64 ml/min and $m_{{\rm ads}} =$ m ads = 4.5 g, whereas $C_0$ C 0 had negligible effect on the response parameters in the range 73–107 mg Zn/l. Finally, three empirical breakthrough curve (BTC) models were employed to describe the individual BTCs of which the modified dose – response model was found to give the best fit (0.960 $\le$ ≤ $R^2$ R 2 $\le$ ≤ 0.998). The results of the present work demonstrate that the novel AAM has considerable potential to be utilized in water purification applications. [ABSTRACT FROM AUTHOR]

Biochar with abundant functional groups, porous structure, and high specific surface area has been widely used as an adsorbent for the removal of metal ions, and its low production costs make it economically suitable for large-scale application in various industries. Hydroxyapatite nanoparticles were used to functionalize magnetic rice husk biochar (MBC) to produce hydroxyapatite functionalized magnetic rice husk biochar (HAP@MBC) in this study. The functional groups, magnetism performance, surface morphology, and aperture structure of HAP@MBC were characterized to explore the feasibility of its application in the treatment of wastewater containing Cu(II) ions. It is found that the maximum adsorption removal rate reaches 96.02% at 35°C, pH=5.0 , with an adsorbent dosage of 0.65 g/L and an initial Cu(II) ion concentration of 50 mg/L. Additionally, adsorption kinetics, isotherms, and thermodynamics were analyzed to probe into the adsorption mechanism of Cu(II) ions by HAP@MBC. The results show that the adsorption process is very close to the pseudo-second-order model, indicating that the adsorption process is mainly controlled by chemisorption. The adsorption of Cu(II) ions can also be fitted by the intraparticle diffusion model, revealing that the adsorption rate is limited by intraparticle diffusion as well as other factors. Moreover, the adsorption process is consistent with the Langmuir isotherm, and the saturated adsorption capacity is calculated to be 81.59 mg/g. Thermodynamic analysis shows that the value of adsorption enthalpy change is 48.35 kJ/mol , suggesting the adsorption process is chemisorption. More precisely, it is a spontaneous entropy-increasing reaction, and an increase in the temperature is conducive to the adsorption. To sum up, HAP@MBC exhibits perfect adsorption properties and has the potential to be a novel and promising adsorbent for the removal of Cu(II) ions. [ABSTRACT FROM AUTHOR]

Water contamination caused by inconsistencies in the removal of contemporary colors and heavy metals constitutes a serious global ecological concern. This study introduces a composite material made of cellulose acetate coated with activated carbon, which is made more effective by including pectic enzymes. This composite is easily manufactured and has caused considerable interest due to its potential in wastewater treatment via absorption‐based techniques for the photocatalytic degradation of methylene blue dye and lead removal. Thermal processing and electrospinning are used in the synthesis process. Field emission scanning electron microscopy (FE‐SEM), Energy Dispersive Xray‐ Analysis (EDX), Brunauer–Emmett–Teller (BET), and UV‐absorbency were used to characterize the resultant pectic cellulose/activated carbon nanofibers (P‐CNFs). In addition, inductively coupled plasma‐mass spectroscopy (ICP‐MS) was used to evaluate lead ion adsorption. Several parameters, including initial lead ion and methylene blue concentrations, solution pH, and nanofiber, were investigated. Fifty percent of pectic‐containing composite (cellulose/activated carbon) P‐CNF has shown remarkable differences when compared to non‐pectic and different ratio composite due to higher surface area and porosity. It also increases light absorption and decreases charge recombination, resulting in a maximum degradation efficiency of 98.5% in a neutral solution under UV‐light irradiation for 25 min, compared to pure CNF (degradation efficiency is 49% after 60 min of irradiation). In the case of lead removal, 80% efficiency was achieved in 5 min. [ABSTRACT FROM AUTHOR]

The objective of the research outlined in this article was to gain a deeper understanding of the microbiome involved in the bioremoval of Pb under continuous flow conditions. A continuous lead removal system, utilizing an upflow anaerobic sludge blanket reactor (UASB) was employed to remove Pb(II) while monitoring factors such as microbial growth along with Pb(II) and nitrate concentrations at two axial heights in the system. The microbiome was assessed to identify any alterations resulting from changing the amounts of Pb(II) in the reactor feed. The UASB was operated under anaerobic conditions, and a nutrient-rich broth comprising exclusively of 5 g/L yeast extract (YE) along with 1g/L of sodium chloride (NaCl) served as the growth medium. The results indicated an effective, robust method of Pb(II) removal. In this study the growth medium was spiked with: 80, 500 and 1000 ppm of Pb(II). The results showed that lower concentrations of Pb(II) were effectively removed with only 5 g/L YE, suggesting a cost-effective option for Pb(II) bioremoval. A maximum Pb-removal rate of 350.6 ppm/d Pb(II) and a maximum specific growth rate of 2.25 per day were observed. Increased concentrations of Pb(II) resulted in reduced metabolic activity (MA) and Pb removal. As is, the system is able to achieve approximately 100% of lower concentrations of Pb and increasing the yeast extract concentration could improve the system. This is the first known study conducted on a continuous flow column Pb(II) removal system. It provides a basis towards developing methods to remove lead (and by extension other heavy metals) which can be carried out at ambient temperatures. This study also provides basis for development of methods to recover and reuse lead from industrial effluents and lead waste sites. [ABSTRACT FROM AUTHOR]

For the serious situation of heavy metal pollution, the use of cheap, clean, and efficient biochar to immobilize heavy metals is a good treatment method. In this paper, SA@ZIF-8/BC was prepared for the adsorption of Pb2+ in solution using sodium alginate (SA) and zeolitic imidazolate framework-8 (ZIF-8) modified corn cob biochar. The results showed that the specific surface area of modified biochar was greatly improved, with good adsorption capacity for Pb2+, strong anti-interference ability, and good economy. At the optimal adsorption pH of 5, the adsorption model of Pb2+ by SA@ZIF-8/BC was more consistent with the pseudo-second-order kinetic model and Langmuir isotherm model. This indicates that the adsorption of Pb2+ by SA@ZIF-8/BC is chemisorption and monolayer adsorption. The maximum adsorption of modified biochar was 300 mg g−1, which was 2.38 times higher than that of before modified BC (126 mg g−1). The shift in binding energy of functional groups before and after adsorption of SA@ZIF-8/BC was studied by XPS, and it was found that hydroxyl and carboxyl groups played an important role in the adsorption of Pb2+. It was demonstrated that this novel adsorbent can be effectively used for the treatment of Pb pollution in wastewater. [ABSTRACT FROM AUTHOR]

To effectively enhance the resource utilization of biomass waste and realize waste recycling, a novel acid-modified magnetic biomass spent tea leaves (NiFe2O4/STLs) was prepared via the pyrolysis and co-precipitation methods and employed to eliminate bivalent mercury (Hg(II)) from water bodies. The as-prepared NiFe2O4/STLs exhibited strong magnetic property of 35.36 emu g−1 and could be easily separated from water by applying a magnetic field. The adsorption of Hg(II) over NiFe2O4/STLs was achieved under the optimal conditions of pH = 8 and T = 30 °C, and the maximum adsorption capacity towards Hg(II) was 204.42 mg g−1 according to the response surface methodology optimization. The removal of Hg(II) over NiFe2O4/STLs primarily involved ion exchange, electrostatic attraction and chelation, following the pseudo-second-order kinetic and Langmuir models, and attributed to an exothermic reaction. In addition, the magnetic biomass NiFe2O4/STLs exhibited good regeneration capability and chemical and mechanical stability. The application results revealed that inorganic salt ions, the nitrogen fertilizer urea, humus and other impurities in four different actual water bodies (tap water, river water, lake water and the effluent of sewage treatment plant) had a little impact on the adsorption of Hg(II) over NiFe2O4/STLs. The as-obtained biomass adsorbent of NiFe2O4/STLs has good application value for the removal of the toxic element Hg(II) from water bodies. [ABSTRACT FROM AUTHOR]

Activated carbon from apricot seeds (ASAC) was successfully made using a low-cost, straightforward synthesis process. With the use of various instruments, including XRD, XPS, FT-IR, SEM, and TEM, the adsorbent was demonstrated. The surface area of the ASAC that was given was also shown to be 436.8 m2/g. It was discovered that the synthesized ASAC has a fantastic capacity to absorb the anti-cancer medication doxorubicin hydrochloride (DOX). Based on changes in temperature, pH, and DOX concentration, The DOX adsorption behaviour's mechanism was evaluated. The adsorption capacity of ASAC for DOX was greater at pH 6.0, according to experimental data as the adsorption capacity was discovered to be 951.13 mg/g. Adsorption equilibrium analysis revealed that, when compared to the other models, the Langmuir adsorption provided the best fit to the data that were collected. Additionally, The ASAC has validated the DOX activation energy of adsorption as a chemisorption technique. The kinetics of adsorption were shown to be fitted to pseudo-second-order kinetic model. The reaction was endothermic and spontaneous, according to thermodynamic data. Innvestigation the removal efficiency of ASAC to remove DOX from real watrer sample (tap water, effluent wastewater, and impact wastewater). It was suggested by the results that ASAC was a viable option for treating wastewater and adsorbing DOX. The synthesized ASAC has noteworthy cyclability and reusability characteristics due to its high efficiency (up to five cycles) and low cost (around 86 percent). [ABSTRACT FROM AUTHOR]

Four novel magnetic-activated carbons (MACs) were prepared, characterised, and used as adsorbents to remove heavy metal ions from wastewater samples. The MACs prepared, are advanced adsorbents for the removal of Hg(II), Cr(III), Cd(II), and Pb(II). The nature of the acid, amount, composition of the MACs, and the remotion time were evaluated in aqueous solutions. The ions removal percentages obtained, under the best conditions, were 93% for Hg(II) and higher than 99% for Pb(II), Cr(III), and Cd(II) (100 mg L−1, initial concentration in solution), with 100 mg of the MAC-3 in HNO3 3 mM. The capacity of the best adsorbent, MAC-3, for removing heavy metals ions Hg(II), Cr(III), Cd(II), and Pb(II) was studied using Langmuir and Freundlich adsorption isotherms under the best condition. The maximum adsorption capacities of Hg(II), Cr(III), Cd(II), and Pb(II) were found to be 10.72, 11.51, 11.49 and 11.49 mg g−1, the values of constants of Freundlich models were 17.98, 26.83, 9.18, and 7.18 mg g−1 respectively. For Hg(II) and Pb(II) the correlation factor (R2) was better for Freundlich model, while Cr(III) and Cd(II) showed better R2 with Langmuir model. Finally, the treatment for the elimination of heavy metal ions was carried out, with wastewater samples of industrial and domestic origin, and used for crop irrigation. The samples were collected in Irrigation District 003, Hidalgo, Mexico. The MAC-3 removes heavy metal ions from the wastewater matrix above 99%. [ABSTRACT FROM AUTHOR]

The presence of heavy metal ions in water environments has raised significant concerns, necessitating practical solutions for their complete removal. In this study, a combination of adsorption and electrocoagulation (ADS + EC) techniques was introduced as an efficient approach for removing high concentrations of nickel ions (Ni2+) from aqueous solutions, employing low-cost sunflower seed shell biochar (SSSB). The combined techniques demonstrated superior removal efficiency compared to individual methods. The synthesized SSSB was characterized using SEM, FT-IR, XRD, N2-adsorption–desorption isotherms, XPS, and TEM. Batch processes were optimized by investigating pH, adsorbent dosage, initial nickel concentration, electrode effects, and current density. An aluminum (Al) electrode electrocoagulated particles and removed residual Ni2+ after adsorption. Kinetic and isotherm models examined Ni2+ adsorption and electrocoagulation coupling with SSSB-based adsorbent. The results indicated that the kinetic data fit well with a pseudo-second-order model, while the experimental equilibrium adsorption data conformed to a Langmuir isotherm under optimized conditions. The maximum adsorption capacity of the activated sunflower seed shell was determined to be 44.247 mg.g−1. The highest nickel ion removal efficiency of 99.98% was observed at initial pH values of 6.0 for ADS and 4.0 for ADS/EC; initial Ni2+ concentrations of 30.0 mg/L and 1.5 g/L of SSSB; initial current densities of 0.59 mA/cm2 and 1.32 kWh/m3 were also found to be optimal. The mechanisms involved in the removal of Ni2+ from wastewater were also examined in this research. These findings suggest that the adsorption-assisted electrocoagulation technique has a remarkable capacity for the cost-effective removal of heavy metals from various wastewater sources. [ABSTRACT FROM AUTHOR]

A blend of polymer wastes viz. polyethylene terephthalate (PET) and waste tire rubber (WTR), was implemented to create a novel activated carbon (AC) using KOH-activation. The AC was then applied in synthesizing the MnO/AC composite. The typical adsorbents were identified using XRD, BET surface area, pore volume, EDX, and FESEM. The adsorbents were employed to expel dibenzothiophene (DBT) from model fuel (200 ppm DBT in n-hexane). The adsorptive desulfurization (ADS) of 25 mL of model fuel by the AC amounted to 99.27% at 30°C for 15 min, and 0.35 g of the AC. At the same time, the MnO/AC composite exhibited the superlative extraction of DBT from the model fuel employing 0.35 g MnO/AC composite at 30°C for a 30 min extraction period. The adsorption consequences fitted best to the Freundlich model rather than the other models, whereas the pseudo-2nd-order kinetic averred the adsorption kinetics better than other models. The produced adsorbents were recoverable and thermally stable, resulting in a high elimination efficiency up to the 5 cycles of reuse. In conclusion, the said blend of waste polymers could be implemented as a low-cost and potentially valuable feedstock for producing effective adsorbents for desulfurizing transportation fuel. [ABSTRACT FROM AUTHOR]

Textile industries use large amounts of water as well as dyes. These dyes containing water are then discharged into the water bodies causing a significant role in water pollution. Brilliant Green dye contributes to many harmful diseases related to the respiratory and gastrointestinal tract. In this study, Symplocos racemosa (SR) agro-waste was chemically treated with acid (SR-HCl) and base (SR-NaOH) and then used for removing Brilliant Green Dye (BGD) on the batch scale. They were characterized by SEM, EDX, FTIR, XRD, TGA and DSC. Optimized conditions were 30 °C temperature, pH 6, adsorbent dose of 0.10 g/25 ml dye solution, shaking speed of 100 revolutions per minute, initial dye concentration of 50 ppm and 35 min time for shaking adsorbent and dye solution. Adsorption data obtained were analyzed using isotherms. The experimental data was found to fit well with the Langmuir model and the maximum adsorption capacity (qmax) of BGD on the SR, SR-HCl, and SR-NaOH was revealed to be 62.90, 65.40, and 71 mg/g respectively. Kinetic data (pseudo-first-order and pseudo-second-order) were evaluated and adsorption tends to follow the pseudo-2nd-order, which indicated the chemisorption mechanism. The results revealed that Symplocos racemosa agro-waste can be considered as the potential biosorbent. [ABSTRACT FROM AUTHOR]

Adsorbents based on agricultural biomass have been subjected to several investigations in recent years owing to their low cost and promising adsorption capabilities. This paper aimed to demonstrate the efficiency of date pits activated with phosphoric acid as common activating agent that increases the porosity and surface area of date pits. This results in a greater number of binding sites for the heavy metals to attach to improving the bio-adsorbent's effectiveness. To get rid of heavy metals such as zinc and copper ions from industrial wastewater using a fixed bed with a continuous flow configuration, the derived adsorbent was tested under a variety of operating conditions, including a flow rate of 4-12mL/min, an initial metal ion concentration of 30-60mg/L, and temperatures ranging from 20 to 50°C, which were chosen based on industrial conditions and available data. The results revealed that the removal efficiency of heavy metals increased with an increase in the initial metal ion concentration, but conversely, it decreased with an increase in flow rate and temperature. Also, the results indicated that with the optimum conditions of 15cm static bed height, 60mg/L initial metal concentration, 8mL/min flow rate, and 25°C temperature, determining the ideal conditions results in the efficient removal of pollutants in less time and the treatment of larger quantities. Mathematical modeling of the fixed bed column was achieved using the kinetic models of Adams Thomas, Yoon-Nelson, Bohar, and Modified Dose-Response, in this regard, the Thomas model is the closest to the experimental values, it is supposed that the adsorption mechanism was a Langmuir type adsorption followed by a pseudo-second-order chemical sorption. The Yoon-Nelson approach was employed on experimental data to predict breakthrough curves through nonlinear regression. This made it easier to determine the crucial characteristic column parameters for process design. According to thermodynamic studies, heavy metals spontaneously and exothermally adsorb activated carbon in date pits. Firstly, spontaneous adsorption indicates efficient processes that occur favorably without external energy input, offering cost-effective solutions for various applications. Secondly, the exothermic nature of adsorption suggests that lower temperatures may be sufficient, reducing energy consumption and preserving the stability of sensitive materials. Additionally, the process's exothermicity facilitates desorption at higher temperatures, enhancing the efficiency of regeneration processes. This study has shown that BDP can successfully remove heavy metals from aqueous solutions. Understanding these characteristics is crucial for optimizing applications, reducing costs, and improving overall efficiency in industrial and environmental contexts. [ABSTRACT FROM AUTHOR]

Eragrostis tef (Teff) is one of the most important staple crops in Ethiopia. The straw obtained from teff is a plentiful source of lignocellulosic biomass. In the present study, straw obtained from teff grass was exploited as a carbon precursor to synthesise the activated carbon via chemical activation followed by microwave-aided pyrolysis. The prepared activated carbon by microwave aided method from teff straw (MATSAC) was utilised as a bio-adsorbent to examine the lead II ions adsorption potential from the aqueous medium. RSM technique was employed to explore a process model which correlates the four independent variables namely Pb(II) ions initial concentration, MATSAC dose, adsorption time, and solution pH. Further, the model was statistically optimised to achieve optimum Pb(II) ions removal. They were discovered to be Pb(II) ions initial concentration: 94.35 mg/L, MATSAC dose: 0.655 g/100 mL, adsorption time: 87.6 min, and solution pH: 5.4 to achieve the maximised removal of Pb(II) (90.89%). In the investigation on the models of isotherm, it was inferred that Langmuir isotherm fitted excellently to the equilibrium data of the adsorption. The adsorption capacity of Pb(II) on MATSAC was 42.97 mg/g. In addition, the kinetic analysis confirmed that the process of adsorption was statistically significant to pseudo 2nd order. The thermodynamic study indicated that the negative value of ∆Go deep-rooted the practicability and spontaneity of MATSAC for Pb(II) ions removal. In a nutshell, MATSAC, which is derived from locally available agricultural waste, can remove toxic Pb(II) ions from contaminated water at a minimal cost. [ABSTRACT FROM AUTHOR]

Novel nanocomposite sorbent was produced by depositing nanostructured water treatment residual (nWTR) onto zeolite (Ze) using high-energy ball milling process. The physicochemical properties of nanocomposite (Ze-nWTR) prior and after Cd adsorption were analyzed by SEM–EDX, FTIR, BET and XRD. A batch study of cadmium adsorption (Ze-nWTR) was performed at various process parameters (sorbent dose, contact time, solution pH, competing ions, initial concentration and temperature). The obtained data were fitted to various equilibrium and kinetics models. The Langmuir and power function models successfully described Cd adsorption equilibrium and kinetic processes, respectively. The maximum adsorption capacity (qmax) value of Cd by Ze-nWTR nanocomposite (147 mgg−1) was 3 and 5.9 times higher than those of nWTR and zeolite sorbents, respectively. Increasing temperature from 287 to 307 K has resulted in increasing the maximum Cd adsorption capacity (qmax) of the nanocomposite from 147.9 to 270 mgg−1. The calculated thermodynamics parameters suggested physical and chemical attraction between Cd and Ze-nWTR and the association of dissociative mechanism in Cd(II) sorption process. The excellent reusability and Cd removal ability of Ze-nWTR nanocomposite (98%) from industrial wastewater confirm its potential as promising adsorbent for wastewater treatment applications. [ABSTRACT FROM AUTHOR]

In the present study, activated carbon decorated with zirconia nanoparticle composite (ZrO2/AC) have been prepared using hydrothermal method and then utilized as an adsorbent for the removal of arsenite from aqueous solution. The composite is composed of highly agglomerated ZrO2 particles on AC surface. The high surface area of the synthesized adsorbent results in its high adsorption capacity toward arsenite. Adsorption isotherm and kinetic data of arsenite adsorption process can be well fitted to the Langmuir isotherm with maximum monolayer adsorption capacity of 64.00 mg.g-1. The experimental results suggest that the adsorption process of arsenite onto ZrO2/AC material involves the formation of both outer-sphere and inner-sphere complexes between arsenite and adsorbent. The high adsorption ability toward arsenite as well as the high recyclable nature of this material makes it a potential alternative material for the removal of toxic heavy metals from wastewater. [ABSTRACT FROM AUTHOR]

In this work, sodium alginate/sodium humate @ Polyacrylamide (SA/SH@PAM) hydrogel beads were prepared using sodium alginate as encapsulant, sodium humate as filler, and polyacrylamide wrapped on the outer layer. Removal and recycling performance toward batch and column adsorption of Cu (II) was investigated. The results indicated that SA/SH@PAM had good removal behavior in the pH range of 3.0–6.0, with an optimal pH of 5.0. The maximum adsorption capacity of SA/SH@PAM beads could reach ~ 134.65 mg/g, which was 2.0 and 1.6 times higher than that of sodium alginate beads (SA) and sodium alginate/sodium humate beads (SA/SH), respectively. Pseudo-second-order kinetic model could fit experimental data better, indicating the chemisorption of Cu (II) on SA/SH@PAM surface. Isotherm and thermodynamics studies suggested that heterogeneous multilayer adsorption occurred on the surface of SA/SH@PAM and Cu (II) adsorption was a spontaneous and endothermic process. Thomas model was fitted better than Adams-Bohart model with breakthrough curves in a fixed-bed column system, signifying that internal and external diffusion was not the main factor limiting the adsorption efficiency of SA/SH@PAM. Characterization analysis (FT-IR, SEM, XPS, etc.) indicated ion exchange and the interaction of multiple functional groups (-COOH, -CO–NH-, etc.) with Cu (II) were the main adsorption mechanisms. Besides, SA/SH@PAM demonstrated good regeneration and anti-interference ability of co-existing ions. Overall, SA/SH@PAM is a potential adsorbent for Cu (II) removal from wastewater. [ABSTRACT FROM AUTHOR]

In order to solve the problem of uranium pollution during the development and application of nuclear energy, magnetic ZnFe2O4/ZrO2(ZFOZO) composite material was synthesized by hydrothermal method to treat uranium containing wastewater. In this study, the surface properties and mechanism of the synthesized ZFOZO were analyzed by various characterization methods. The effects of adsorption time, pH, dosage of adsorbent, coexisting ions, and initial concentration of uranium (VI) solution on the adsorption performance of uranium (VI) by ZFOZO were investigated. ZFOZO exhibited the maximum adsorption rate of 99.8% under the conditions of CU (VI) = 10 mg/L, pH = 6, M/V = 0.3g/L, t =120 min, and T = 303K. The adsorption process was found to be a spontaneous endothermic process and conformed to the pseudo-second-order kinetic model and the Freundlich isothermal adsorption model. The adsorption mechanism of ZFOZO on U (VI) is mainly electrostatic adsorption, surface complexation, and oxygen vacancy. The maximum adsorption capacity of ZFOZO for U (VI) can reach 552.36mg/g. Adsorption–desorption experiment demonstrated that ZFOZO has a good reusability, after five cycles of adsorption and desorption, the adsorption efficiency is still above 75%. Cu2+ and Fe3+ will produce competitive adsorption and reduce the adsorption performance of ZFOZO on U (VI). In summary, this study provides a high efficiency, low cost, and rapid recovery adsorbent for the treatment of uranium containing wastewater in the future. [ABSTRACT FROM AUTHOR]

In this study, the adsorption efficiency of low-cost raw and modified clay was investigated. The modified clay was characterized through various technics including X-ray diffraction, XRF spectroscopy, FT-IR spectroscopy, and Electron microscopy SEM to analyze the evolution of raw clay structure and morphology. Paracetamol was chosen as an adsorbate to evaluate the removal performance from the aqueous medium. Factors influencing the uptake of paracetamol, such as pH, equilibrium time, adsorbent dosage, and initial concentration of paracetamol, were examined. The results obtained showed that the raw clay was successfully modified by HDTMA, which increased adsorption capacity thanks to new hydrophobic interaction. The adsorption of paracetamol on the modified clay reached equilibrium at a contact time of 120 min. Isothermal and kinetic models used in this study showed that the adsorption followed the Langmuir-isotherm and pseudo-second-order kinetic models. The maximum experimental adsorption capacity predicted by Langmuir model is about 112.63 mg/g, which is much higher than that obtained for the unmodified sample (62.11 mg/g). These results show that modified natural Moroccan clay can be used as low-cost and eco-friendly adsorbent nanomaterials to remove emerging pharmaceutical contaminants from water. [ABSTRACT FROM AUTHOR]

The efficient development of selective materials for uranium recovery from wastewater and seawater is crucial for the utilization of uranium resources and environmental protection. The potential of graphene oxide (GO) as an effective adsorbent for the removal of environmental contaminants has been extensively investigated. Further modification of the functional groups on the basal surface of GO can significantly enhance its adsorption performance. In this study, a novel poly(amidoxime-hydroxamic acid) functionalized graphene oxide (pAHA-GO) was synthesized via free radical polymerization followed by an oximation reaction, aiming to enhance its adsorption efficiency for U(VI). A variety of characterization techniques, including SEM, Raman spectroscopy, FT–IR, and XPS, were employed to demonstrate the successful decoration of amidoxime and hydroxamic acid functional groups onto GO. Meanwhile, the adsorption of U(VI) on pAHA-GO was studied as a function of contact time, adsorbent dosage, pH, ionic strength, initial U(VI) concentration, and interfering ions by batch-type experiments. The results indicated that the pAHA-GO exhibited excellent reuse capability, high stability, and anti-interference ability. Specially, the U(VI) adsorption reactions were consistent with pseudo-second-order and Langmuir isothermal adsorption models. The maximum U(VI) adsorption capacity was evaluated to be 178.7 mg/g at pH 3.6, displaying a higher U(VI) removal efficiency compared with other GO-based adsorbents in similar conditions. Regeneration of pAHA-GO did not significantly influence the adsorption towards U(VI) for up to four sequential cycles. In addition, pAHA-GO demonstrated good adsorption capacity stability when it was immersed in HNO3 solution at different concentrations (0.1–1.0 mol/L) for 72 h. pAHA-GO was also found to have anti-interference ability for U(VI) adsorption in seawater with high salt content at near-neutral pH condition. In simulated seawater, the adsorption efficiency was above 94% for U(VI) across various initial concentrations. The comprehensive characterization results demonstrated the involvement of oxygen- and nitrogen-containing functional groups in pAHA-GO in the adsorption process of U(VI). Overall, these findings demonstrate the feasibility of the pAHA-GO composite used for the capture of U(VI) from aqueous solutions. [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]

Banana rachis is an abundant source of cellulose from agricultural waste. Fine-diameter cellulose nanofibrils (CNFs) should have a high capacity for heavy metal removal from wastewater based on a specific surface area. With nitro-oxidation and simple mechanical blending, the banana rachis resulted in individualized cellulose nanofibrils (NOCNFs) of length = 1231 nm, diameter = 5.26 nm, and negatively charged carboxylic groups at the C6 position with degrees of oxidation (DO) from 0.455 to 1.466 mmol/g. The NOCNFs were employed to remove Pb (II) from water and prepare films to investigate the mechanical performance. Increased Pb (II) removal efficiency was observed correlating to the increase in DO (0.455–1.466 mmol/g) and NOCNF concentration in support of a chemisorption mechanism. The NOCNFs showed a maximum adsorption capacity of 1667 mg/g at DO = 0.455 mmol/g, which is very high compared to adsorbents from literature and with the potential to increase at a DO of 1.466 mmol/g. NOCNF films showed impressive mechanical properties in support of high intrinsic NOCNF strength even at high DO: the tensile strength = 254 MPa, Young modulus = 10.7 GPa, and strain to failure = 5.7%. The nitro-oxidation also preserved the long-range cellulose order in the NOCNFs even at high DO with cellulose I crystalline index = 99.999%, essential to the remarkable Pb (II) removal capacity and mechanical performance. The study shows the potential of banana rachis from waste as a sustainable material for water purification and the possibilities of controlled banana rachis CNFs functionalization. [ABSTRACT FROM AUTHOR]

An amphiphilic polymeric chelator (APC16-g-SX) grafted with sodium xanthate (SX) groups was successfully prepared for the efficient removal of high concentrations of Cu(II) from wastewater. The ordinary polymeric chelator (PAM-g-SX) based on linear polyacrylamide (PAM) was also prepared for comparative studies. The polymeric chelators were characterized by Fourier transform infrared spectroscopy (FT-IR), solid-state nuclear magnetic resonance (13C-NMR), gel permeation chromatography (GPC), elemental analyzer, and scanning electron microscope (SEM). The chelating performance of these polymeric chelators was investigated, and the mechanism of APC16-g-SX for enhanced removal of Cu(II) from wastewater was proposed based on fluorescence spectroscopy, cryo-scanning electron microscope (Cryo-SEM), energy-dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS) tests. The results show that as the initial Cu(II) concentration in the wastewater increases, APC16-g-SX shows more excellent chelating performance than ordinary PAM-g-SX. For the wastewater with an initial Cu(II) concentration of 200 mg/L, the removal rate of Cu(II) was 99.82% and 89.34% for both 500 mg/L APC16-g-SX and PAM-g-SX, respectively. The pH of the system has a very great influence on the chelating performance of the polymeric chelators, and the increase in pH of the system helps to improve the chelating performance. The results of EDS and XPS tests also show that N, O, and S atoms in APC16-g-SX were involved in the chelation of Cu(II). The mechanism of enhanced removal of Cu(II) by APC16-g-SX can be attributed to the spatial network structure constructed by the self-association of hydrophobic groups that enhances the utilization of chelation sites. [ABSTRACT FROM AUTHOR]

A novel ethylene-bridged silsesquioxane was synthesized by a heat-induced thiol–ene addition reaction of 2-acetylthioethanethiol to 1,2-bis(triethoxysilyl)ethene. Upon deacetylation, the formed organosiloxane precursor bearing the dithiol moiety (–SCH2CH2SH) self-assembled into a sulfur-rich PMO material in the presence of the structure-directing agent under acidic conditions. The loading of sulfur-bound ligands in the PMO framework can be adjusted by co-condensing the precursor with tetraethyl orthosilicate. The structure of the resulting PMOs was characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, and nitrogen adsorption and desorption studies. The PMO prepared by using the thio-bis-silane precursor alone can be used for efficient and fast capture of mercury ions from water with a saturation Hg(II) uptake capacity of 1253 mg g−1 and recycled several times with negligible loss in the adsorption efficiency. This material also showed a high adsorption selectivity for Hg(II) over other competitive metal ions like Zn2+, Pb2+, Fe3+, Cu2+ and Mn2+. Remarkably, the new adsorbent proved to be effective for simultaneously removing Hg(II) and rhodamine B (RhB) from simulated sewage with removal rates of over 97% and 91% for both at 100 ppm, respectively, indicating its potential for the practical application in environmental remediation. [ABSTRACT FROM AUTHOR]

• BW has strong acid resistance (pH ≥ 1). • BW selectively separates lead from complex heavy metal solutions. • The selective immobilization is due to its specific composite structure. The development of bio-adsorbents with highly selective immobilization properties for specific heavy metals is a great challenge, but has important application value. Biogenic whewellite (BW) with high selectivity for Pb(II) was synthesized by mineral microbial transformation. The selective immobilization properties and mechanism of BW for Pb(II) were analyzed by combining mineral characterization technology and batch adsorption research methods. The results indicated that BW can efficiently and selectively immobilize Pb(II) in single or composite heavy metal adsorption solutions, and the immobilized Pb(II) is difficult to desorb. BW undergoes monolayer adsorption on Pb(II), Q max ≈ 1073.17 mg/g. The immobilization of Pb(II) by BW is a physico-chemical adsorption process with spontaneous heat absorption and an accompanying increase in entropy. In addition, the sequestration of Pb(II) by BW remains around 756.99 mg/g even at pH = 1. The excellent selective immobilization properties of BW for Pb(II) are closely related to its smaller K sp , electrostatic repulsion effect, organic-inorganic composite structure, acid resistance and the formation of Pb(II) oxalate. This study provides beneficial information about the recycling of lead in acidic lead-containing wastewater and composite heavy metal contaminated water bodies. [Display omitted] [ABSTRACT FROM AUTHOR]

This article explores recent advancements and innovative strategies in biosorption technology, with a particular focus on the removal of heavy metals, such as Cu(II), Pb(II), Cr(III), Cr(VI), Zn(II), and Ni(II), and a metalloid, As(V), from various sources. Detailed information on biosorbents, including their composition, structure, and performance metrics in heavy metal sorption, is presented. Specific attention is given to the numerical values of the adsorption capacities for each metal, showcasing the efficacy of biosorbents in removing Cu (up to 96.4%), Pb (up to 95%), Cr (up to 99.9%), Zn (up to 99%), Ni (up to 93.8%), and As (up to 92.9%) from wastewater and industrial effluents. In addition, the issue of biosorbent deactivation and failure over time is highlighted as it is crucial for the successful implementation of adsorption in practical applications. Such phenomena as blockage by other cations or chemical decomposition are reported, and chemical, thermal, and microwave treatments are indicated as effective regeneration techniques. Ongoing research should focus on the development of more resilient biosorbent materials, optimizing regeneration techniques, and exploring innovative approaches to improve the long-term performance and sustainability of biosorption technologies. The analysis showed that biosorption emerges as a promising strategy for alleviating pollutants in wastewater and industrial effluents, offering a sustainable and environmentally friendly approach to addressing water pollution challenges. [ABSTRACT FROM AUTHOR]

Geopolymer is one of the materials used as an environmentally friendly adsorbent and is produced from wastes such as fly ash at temperatures below 100 °C. Therefore, this study aims to investigate the adsorption process of Cu2+ and Zn2+ on the geopolymer structure by determining the isotherms, kinetics, and adsorption thermodynamics. The synthesis of geopolymer was conducted by varied Na2O/SiO2 ratios and aging time. The adsorption of Cu2+ and Zn2+ on geopolymer followed the Langmuir isotherm with the highest adsorption capacity achieved using R0.3T5 with qm 94.33 mg/g and 87.72 mg/g, respectively. Furthermore, the kinetic studies of the adsorption showed the adsorption process followed pseudo-second-order. The estimated thermodynamic parameters presented a positive value of enthalpy (ΔH°) and a negative value of Gibbs energy change (ΔG°), approving that the adsorption process on Cu2+ and Zn2+ occurs endothermically and spontaneously. More importantly, we found that the adsorption of Cu2+ and Zn2+ was influenced by the Na2O/SiO2 ratio and the pore volume of the geopolymer, which could be the basis for the further design of a more effective adsorbent. [ABSTRACT FROM AUTHOR]

Porous ceramic compound as adsorbents for heavy metal removal was produced by mixing kaolin with charcoal in addition to cobalt ferrite nanoparticles at 0, 3, 5, 7, and 10 wt%. The synthesized magnetic cobalt ferrites, prepared using sol–gel auto-combustion method, were characterized by X-ray diffraction, field emission scanning electron microscopy, and vibrating sample magnetometer, as well as examining the physical and mechanical characteristics of the kaolin/cobalt ferrite composite. PH and adsorbent dose were studied in the context of the adsorption of Pb2+, with a comparison of results against using crushed kaolin/CoFe2O4 powder. The resulting CoFe2O4 nanoparticles have saturation magnetization values of about 48.85 emu/g. Darcy permeability of the porous ceramics prepared by the semi-dry pressing method was increased from 1.9 to 4.6 cm/s; meanwhile, for porous ceramics prepared by the slip casting method, the permeability varied from 5 to 7.9 cm/s. Utilizing kaolin/CoFe2O4 particles, the best removal efficiency for Pb2 + was found to be 100% at pH 3 used 10 wt% of Co-ferrite for samples prepared by slip casting method and 91.9% for samples prepared by semi-dry method. In contrast, the best lead removal efficiency of 89.6% was reported at pH 5 when utilizing crushed kaolin/CoFe2O4 powder, and the removal efficiency increased at high concentrations of lead ions from 16.7 to 96.68%, with the highest adsorption of lead ions obtained at 50 min, reaching a removal efficiency of 83.23%. [ABSTRACT FROM AUTHOR]

In this study, Tarbiat Modares University‐10/poly pyrrole (TMU‐10/PPy), a water‐stable metal–organic framework/polymer composite, was successfully fabricated and applied as adsorbent for removal of methyl red from contaminated water. The pyrrole obtained novel‐structured TMU‐10@PPy composite showed high efficiency in removing the methyl red. Several variables affecting the adsorption efficiency of methyl red, that is, pH, amount of adsorbent, contact times, and the salt additive, were investigated and optimized. The best working conditions were as follows: sample pH, 5; amount of sorbent, 4 mg; contact time, 9 min; salt additive, 2% (wt/vol). The maximum adsorption capacity of TMU‐10@PPy toward methyl red was 101.01 mg/g. The adsorption kinetics and isotherms of TMU‐10@PPy were consistent with a pseudo‐second‐order kinetic model and the Langmuir isotherm model. It was found that TMU‐10@PPy exhibited excellent reusability and had the potential for treating dye‐polluted wastewaters. [ABSTRACT FROM AUTHOR]

Wastewater discharges from industrial processes typically include elevated concentrations of contaminants, which largely consist of potentially harmful chemicals such as heavy metals. These contaminants are characterized by their slow rate of decomposition. Hence, the removal of these metallic ions from effluents poses a challenge. Among different treatments, the adsorption approach has considerable potential due to its ability to effectively eliminate both soluble and insoluble pollutants from effluent, even at lower levels of concentration. Of various wastes, fly ash (FA) material has been the subject of attention because it is abundant, has favorable qualities, and contains a high percentage of minerals. This review investigates multiple facets, with a specific focus on the application of FA, an industrial byproduct, as an adsorbent in removing heavy metals. A comprehensive examination was conducted on a range of concerns pertaining to the pollution caused by metallic ions, including the underlying causes, levels of contamination, health implications of heavy metals, and removal methods. Multiple factors were found to affect the adsorption process. Of all the factors, the pH value considerably influences the elimination of heavy metals. An acidic pH range of 2.5–4.5 was found to be optimal for achieving the highest possible elimination of As(V), Cu(II), Hg(II), and Cr(VI). The latter elimination rate reached 89% at the optimal pH level. Most heavy metals' adsorption isotherms conformed to the Langmuir or Freundlich models, while the pseudo-second-order kinetics provided a satisfactory match for their removal. Using a raw FA, adsorption capacities were achieved in the removal of metallic ions, Ni(II), Pb(II), and Cr(VI), that ranged from 14.0 to 23.9 mg g−1. Meanwhile, the FA-zeolite showed a remarkable capacity to adsorb ions Mn(II), Ni(II), Cd(II), Cu(II), and Pb(II), with values ranging from about 31 to 66 mg g−1. The cost analysis showed that the treatment of FA is economically advantageous and may result in significant cost reductions in comparison to commercial adsorbents. In summary, FA is an inexpensive waste material with potential for water treatment applications and several other purposes due to its excellent chemical and mineralogical composition. [ABSTRACT FROM AUTHOR]

A novel herbal medicinal waste-derived black cardamom (Amomum subulatum) adsorbent was investigated for cadmium (II) removal from water. The biosorbent was characterized by SEM, EDX, XRD, FTIR, and pHZPC. The equilibrium uptake of cadmium (II) from water was studied under the influence of solution pH, contact time, operating temperature, adsorbent dose, cadmium (II) initial concentration, and adsorbent size. The maximum removal of cadmium (II) (96%) through biosorbent was observed at pH of 4, 150–180 micron particle size, initial concentration of 50 mg/L in 50 ml solution having 0.5 g of dose. The cadmium (II) uptake by biosorbent was well fitted by Freundlich isotherm, suggesting multilayer adsorption as Chi-squared and sum of square errors values for the Freundlich isotherm model also lay in narrow range, i.e., 0.009–0.035 and 0.016–0.059, respectively. The higher coefficient of determination values of 0.972–0.997 also indicated a strong fit of the Freundlich model to the experimental data. Kinetic studies suggested appropriateness of the pseudo-second-order model with coefficient of determination values close to 1. Likewise, Chi-squared and normal standard deviation values also fell within smaller ranges of 0.002–0.007 and 0.006–0.016, respectively, for pseudo-second-order model. The thermodynamic evaluation revealed the adsorption of cadmium (II) to be spontaneous, random, and exothermic. The pore volume and surface diffusion model simulated in gPROMS software was used to analyze cadmium adsorption. The simulation results closely fitted with the experimental data. Thus, this novel adsorbent could be a low-cost and efficient alternative for removing cadmium (II) from polluted waters. [ABSTRACT FROM AUTHOR]

The removal of lead metals from wastewater was carried out with carbon microspheres (CMs) prepared from date palm leaflets using a hydrothermal carbonization process (HTC). The prepared CMs were subsequently activated with phosphoric acid using the incipient wetness impregnation method. The prepared sample had a low Brunauer–Emmet–Teller (BET) surface area of 2.21 m2·g−1, which increased substantially to 808 m2·g−1 after the activation process. Various characterization techniques, such as scanning electron microscopy, BET analysis, Fourier transform infrared, and elemental analysis (CHNS), were used to evaluate the morphological structure and physico-chemical properties of the CMs before and after activation. The increase in surface area is an indicator of the activation process, which enhances the absorption properties of the material. The results demonstrated that the activated CMs had a notable adsorption capacity, with a maximum adsorption capacity of 136 mg·g−1 for lead (II) ions. This finding suggests that the activated CMs are highly effective in removing lead pollutants from water. This research underscores the promise of utilizing activated carbon materials extracted from palm leaflets as an eco-friendly method with high potential for water purification, specifically in eliminating heavy metal pollutants, particularly lead (II), contributing to sustainability through biomass reuse. [ABSTRACT FROM AUTHOR]