Sorbent Dosage Research Articles

A covalent organic framework-derived pretreatment for pesticides in vegetables and fruits

Sample pretreatment is an essential procedure in pesticide analysis, as the matrix effect can significantly influence the results. In this study, a covalent organic framework (COF) was synthesized using 1,2,4,5-tetrakis-(4-formylphenyl)benzene (TFPB) and benzidine (BD) to mitigate the matrix effect in vegetable and fruit samples. This COF was then used to develop a solid-phase extraction (CSPE) method. In addition, the COF was used to create a magnetic COF (MCOF) for use in magnetic solid-phase extraction (MSPE). The synthesized COF and MCOF were thoroughly characterized using scanning electron microscopy (SEM) for morphological analysis, Fourier-transform infrared spectroscopy (FT-IR) for chemical bond identification, and N2 adsorption–desorption measurements for porosity and surface area assessment. Key pretreatment parameters such as buffers, dilution rate, sorbent dosage, extraction time, elution solvent, and reuse number were optimized. The developed CSPE and MSPE showed excellent purification ability for the matrix of vegetable and fruit samples. The reuse test demonstrated that the synthesized COF and MCOF can be reused up to 15 times. Moreover, the developed CSPE and MSPE showed acceptable recoveries in spiked recovery tests, suggesting that these pretreatment methods were feasible for sample purification in pesticide analysis.

Removal of metaldehyde and acetamiprid by extracted cellulose from biomass incorporated with copper after acetylation

The presence of pesticides in water have reached to an alarming level in some parts of the world and have caused deteriorating effects on human health. Reclamation of portable water from such contaminants have become mandatory. Scientists around the world are trying to devise new methods of water purification. The target can be achieved either by limiting the use of pesticides for agriculture purposes or by devising unique methods for their recoveries from contaminated water. In this context, herein cellulose has been extracted from Populus nigra, subjected to acetylation using acetic acid in the acidic medium (sulfuric acid). The modified acetylated cellulose was treated with Cu-based salt to enable the metallic combination. The prepared sorbent was characterized by UV, SEM, EDX, XRD, and FTIR techniques. Two insecticides; metaldehyde and acetamiprid in synthetic waste-water solution were subjected for adsorption on the modified sorbent in a series of experiments to evaluate the impact of contact time, sorbent dosage, pH, and temperature. Optimum conditions established in a series of experiments such as 80 and 60 min of contact time for acetamiprid and metaldehyde respectively, pH of 8 and 9 (slightly basic) correspondingly for the mentioned pesticides, and a 0.08 g adsorbent dosage were used in the estimation of kinetics and isothermal parameters. The kinetic data successfully followed the pseudo-second-order kinetic model whereas, the isothermal data was found to be best fitted by Langmuir isotherm model in the case of acetamiprid and by Freundlich in the case of metaldehyde. The regeneration study was performed for both the pesticides showing more than 70 % removal capabilities of fabricated adsorbent after three consecutive cycles. The prepared adsorbent could be a better alternative of commercial activated carbon however, further experiments are encouraged to investigate the full environmental application spectrum of the fabricated sorbent.

Chemical modification of Pinus walliichiana sawdust: Application in membrane system for efficient purification of groundwater containing Cd(II) and Ni(II)

In the Sargodha region of Pakistan, the concentrations of Cd(II) and Ni(II) ions are very high as compared to WHO and US EPA standards and may be one of the leading reasons for water-borne diseases in the population of this area. In the current research work, an eco-friendly, low-cost, effective, and reusable filter membrane system is developed. The cellulose sawdust of Pinus walliichiana (PWC) was treated with succinic anhydride to form Pinus walliichiana cellulose succinate (PWCS) and finally converted to sodic form (PWCS-Na) by treating with saturated sodium bicarbonate. The PWCS and PWCS-Na as obtained were characterized using FTIR, pHZPC, SEM, PXRD, and Brunauer–Emmett–Teller (BET) analysis. The BET surface area of the PWCS-Na was found to be 579.5 m2/g. Maximum sorption capacity values in the batch study for Cd(II) (235.2 ± 10.3 mg g−1) and Ni(II) (195.6 ± 15.2 mg g−1) were observed at 298 K, pH 6, sorbent dosage of 30 mg, and metal ion concentration of 70 mg/L. The filter membrane system was designed and employed for the purification of the flowing water system. Theoretical calculations show that 1 L of filter membrane containing 138.0 g of the adsorbent PWCS-Na can purify 532.8 L solution with Cd(II) concentration 70 mg/L and 278.2 L solution of Ni(II) with concentration 70 mg/L. The regeneration study proved the efficient reusability of sorbent after five cycles with a slight change in sorption capacity.

Development of free flowing granular hybrid functionalized clay sorbent filters for chromium removal from waste water

Chromium (VI) contamination in water resources at industrial sites poses significant environmental and health risks. Conventional sorbents often suffer from limitations such as clogging, back pressure, poor kinetics, and challenges in coupling with flow systems and regeneration. This study focuses on developing, characterizing, and applying free-flowing granular (FFG) amidoxime-functionalized montmorillonite (Mt) clay sorbents (AO-Mt-H-C) to enhance chromium (VI) removal from contaminated waste water. Batch adsorption experiments demonstrated that AO-Mt-H-C outperformed montmorillonite clay modified with quaternary ammonium alone (Mt-H-C), achieving a Cr (VI) removal efficiency of 50.6 mg g−1 compared to 44.3 mg g−1, due to the synergistic interactions of quaternary ammonium and amidoxime functionalities. To address the limitations of conventional sorbents, such as clogging and poor kinetics, an FFG filter column was developed and tested, showing effective Cr (VI) removal across various water sources with minimal interference in drinking and groundwater. In industrial wastewater with higher matrix loads, over 99 % removal efficiency was achieved with a 25 % increase in sorbent dosage. Desorption and reusability assessments confirmed the AO-Mt-H-C's effectiveness across three cycles. Mathematical modelling using Thomas and Yoon–Nelson equations supported the design of customized treatment systems. Scalability was demonstrated by treating 1.6 m3 of textile industrial effluents (100 mg L−1 Cr (VI)) with quantitative removal efficiency (>99.5 %). This study illustrates that the hybrid functionalization and free-flowing granulation of clay sorbent materials significantly enhance Cr (VI) removal, providing valuable insights for advanced water pollution mitigation and environmental sustainability.

Green synthesis of graphene oxide and magnetite nanoparticles and their arsenic removal efficiency from arsenic contaminated soil

Graphene-based nanomaterials have been proved to be robust sorbents for efficient removal of environmental contaminants including arsenic (As). Biobased graphene oxide (bGO-P) derived from sugarcane bagasse via pyrolysis, GO-C via chemical exfoliation, and magnetite nanoparticles (FeNPs) via green approach using Azadirachta indica leaf extract were synthesized and characterized by Ultraviolet-Visible Spectrophotometer (UV-vis.), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), mean particle size and Scanning electron microscopy (SEM) along with Energy dispersive spectroscopy (EDX) analysis. Compared to cellulose and hemicellulose, the lignin fraction was less in the precursor material. The GOC, bGO-P and FeNPs displayed maximum absorption at 230, 236, and 374 nm, respectively. FTIR spectrum showed different functional groups (C-OH, C-O-C, COOH and O-H) modifying the surfaces of synthesized materials. Graphene based nanomaterials showed clustered dense flakes of GO-C and thin transparent flakes of bGO-P. Elemental composition by EDX analysis of GO-C (71.26% C and 27.36% O), bGO-P (74.54% C and 24.61% O) and FeNPs (55.61% Fe, 4.1% C and 35.72% O) confirmed the presence of carbon, oxygen, and iron in synthesized nanomaterials. Sorption study was conducted with soil amended with different doses of synthesized nanomaterials (10, 50 and 250 mg) and exposed to 100, 300 and 500 ppm of As. Arsenic concentrations were estimated by colorimetry and atomic absorption spectroscopy (AAS). GO-C, bGO-P, and FeNPs showed substantial As removal efficiency i.e., 81 to 99.3%, 65 to 98.8% and 73.1–89.9%, respectively. Green synthesis of bGO-P and magnetite nanoparticles removed substantial amounts of As compared to GO-C and can be effectively deployed for As removal or immobilization. Higher and medium sorbent doses (250 and 50 mg) exhibited greater As removal and data was best fitted for Freundlich isotherm evidencing favorable sorption. Nevertheless, at low sorbent doses, data was best fitted for both models. Newly synthesized nanomaterials emerged as promising materials for As removal strategy for soil nano-remediation and can be effectively deployed in As contaminated soils.

Recovery of precious metals from aqua regia leachate of E-wastes using dithiocarbamate-modified cellulose and development of novel kinetic model

The escalating demand and dwindling natural supplies of precious metals (PMs) necessitate innovative hydrometallurgical recovery approaches with rapid kinetics and reduced environmental impact. The current study investigated the sorption and recovery of PMs from electronic waste (e-waste) utilizing dithiocarbamate-modified cellulose (DMC) and its proline derivative with epoxy cross-linkage (DMC-Pro-Epo-6) in aqua regia (AR). The effects of various sorption parameters, such as sorbent dose in feed, HCl: HNO3 ratio, AR dilution times, etc., on PM recovery were explored. Equilibrium for AuIII and PtIV sorption by DMC and DMC-Pro-Epo6 was reached in less than an hour, which is significantly faster than most reported sorbents. The maximum sorption capacities, calculated using the Langmuir equation, were 348.0 mg g−1 for AuIII and 34.7 mg g−1 for PtIV for DMC, while DMC-Pro-Epo6 achieved 350.3 mg g−1 for AuIII and 31.1 mg g−1 for PtIV. These capacities, particularly for the higher sorption capacity of AuIII by DMCs, are attributed to the relativistic effects of gold, soft–soft interactions, and strong sulfur binding. FT-IR, FE-SEM, and EDX analyses elucidated the chelation bonding and mechanisms involved in PM sorption onto DMCs. By utilizing AR-DMC integrated techniques, step-by-step protocols were established for Au recovery from diverse e-waste sources, such as smartphones and smart chip cards. The study also highlighted the importance of chemical pre-concentration of e-waste to remove base metals, facilitating efficient PM recovery. Finally, a key innovation of this work is introducing a new pseudo-mix order fractional model, based on the preference of active sites with fractional assumptions, which more accurately correlates the complex sorption kinetics observed in complex systems.

Synthesis and Characterization of Low-Cost Zirconium Nanocomposites as Novel Adsorbents for Arsenazo III Pollutant

Removing contaminated Arsenazo III dye from contaminated effluent is a challenge and of great interest due to its hazard and environmental impact. Therefore, the biggest challenge was producing highly efficient, easy to recycle, and economically inexpensive adsorbent materials for the contaminated dye. Three chemically stable zirconium nanocomposites with unique properties were synthesized by gel-precipitation technology. The composition, chemical, and physical properties of zirconium molybdate, tungstate, and silicate nanocomposites have been extensively proven using many different and appropriate devices such as XRD, SEM–EDX, TEM, FT-IR, BET, DLS, TGA-DTA, and zeta potential. By utilizing the most effective adsorption techniques, Azo-dye was successfully bound to ZrMo-NPs, ZrW-NPs, and ZrSi-NPs composites. The uptake capacities for these composites were measured at 0.29, 0.79, and 1.61 mmol.g−1, respectively. The sorption parameters were optimized as follows: a feed solution pH of 3 for ZrMo-NPs, a pH of 2.3 for ZrW-NPs, and a pH of 2.3 for ZrSi-NPs. The stirring time was set at 30 min, the metal ion concentration was 1.64 mmol L−1, and the sorbent dose was 7.5 mg. The adsorption results agreed well with the Langmuir isotherm and the pseudo-second-order reaction models and demonstrated the endothermic nature and kinetic improvement by increasing temperatures. The three nanocomposites effectively eliminated tainted dye from lab wastewater, offering promise for their potential applications in the future.Graphical

Metal adsorption equilibrium response of iron oxide nanoparticles embedded on Acacia (Vachellia nilotica) wood waste under different parametric conditions

The present study reveals cost-effective, environmentally approachable, and efficient adsorbent for the elimination of heavy metals by utilizing the biological synthesis route of nanoparticles (NPs). IONPs (hematite) synthesized from Vachellia nilotica wood waste. Raw wood waste and IONPs were characterized by SEM and FTIR. A batch adsorption process was conducted to study the adsorption of lead (Pb+2) and (Cu+2) ions by raw wood waste and IONPs synthesized from wood waste. Parameters like pH change, temperature, dosage of sorbent, and contact time were performed to provide information about optimal conditions for adsorption. It was found that an adsorbent dosage of 4 g, pH = 7, temperature = 120 °C, and time of 20 min provided high removal efficiency of both metals. With Langmuir and Freundlich adsorption isotherm, experimental data matched well with a high adsorption capacity of 7.5 mg/L for Cu (II) and 0.83 mg/L for Pb (II). Kinetics study shows that equilibrium data supports with pseudo-second-order model with the highest R 2=0.99. Thermodynamics study (ΔGo, ΔHo, and ΔSo) shows that the process is feasible and has an endothermic nature. IONPs provide high removal efficiency with R 2=0.99 with both metals. IONPs proved as efficient adsorbents with high removal efficacy of studied metal as paralleled to raw wood waste.

The Application of Wood Biowaste Chemically Modified by Bi2O3 as a Sorbent Material for Wastewater Treatment

Textile dyes discharged into aquatic systems can have significant environmental impacts, causing water pollution and toxicity to aquatic life, and constituting a human health risk. To manage these effects, the sorption ability of wood biowaste chemically modified by Bi2O3 for textile dye removal was investigated. Sorbent characterization was performed using scanning electron microscopy, and elemental analysis by energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), the Brunauer–Emmett–Teller (BET) method for the specific surface area, and Fourier transform infrared spectroscopy–attenuated total reflectance (FTIR-ATR). The optimization of the sorption process was carried out, and optimal parameters, such as contact time, pH, the dose of sorbent, the concentration of dye, and temperature, were defined. Also, desorption studies were conducted. Kinetics and isotherms studies were carried out, and the data fits to a pseudo-second order model (r2 ≥ 0.99) and Langmuir model (r2 ≥ 0.99), indicating that the process occurs in the monolayer form and the dye sorption depends on the active sites of the sorbent surface. The maximal sorption capacity of the sorbent was 434.75 mg/g.

A detailed practical and theoretical study of the adsorptive potential of synthesised ceria impregnated activated graphite for aqueous Se(IV) and Te(IV) removal: Process optimisation, characterisation and mechanistic approach

A cost-effective, simple, and earth friendly nanocomposite adsorbent was synthesized by in - situ penetration of ceria nanocrystals on graphite to remove aqueous selenium (IV) and tellurium (IV). Batch experiments optimize parameters such as pH, temperature, sorbent dosage and equilibration time of 30 minutes. The adsorbent exhibited the maximum adsorption capacities of 144.5 mg/g for Te(IV) and 29.3 mg/g for Se(IV). BET analysis revealed a specific surface area of 16.44 m²/g, an average pore diameter of 4.24 nm, and a high pore volume of 0.0519 cm³/g. The adsorbent was characterized before and after adsorption by SEM-EDX, XRD and FTIR. The sorption data could be well interpreted by the Langmuir model for both Se and Te and by the DR isotherm for Te(IV) at ambient temperature. Kinetic empirical data correlated positively with pseudosecond order for both Se and Te and the Elovich model for Te at room temperature. Kinetics and equilibrium isotherms suggested that the adsorption occurred through surface adsorption using electrostatic bonding along with physisorption involving steady diffusion and accommodation of analyte ions into mesopores and defects of the adsorbent. Chemisorption by electron transfer of the oxyanions of Se/Te with Ce3+/Ce4+ of the cerium impregnated graphite (CIAG) and ion exchange with functional groups on the activated graphite edges were other probable mechanisms. The adsorbent demonstrated the ability to be regenerated and reused over multiple cycles, with minimal interference from coexisting ions emphasizing its selectivity. All measurements were conducted in triplicate with the relative standard deviation (RSD) below 5 %. The optimised method was successfully applied in natural water samples from various sources, demonstrating strong potential for scaling up to field applications.

Encapsulation of Bamboosa vulgaris culms derived activated biochar into hierarchical permeable, phosphate rich and functionalized alginate aerogel composites and its contribution in U(VI) adsorption

In this study, a facile methodology was designed to encapsulate Bamboosa vulgaris culms derived activated biochar (BVC) in a variable mass ratio, into a three-dimensional hierarchical porous and permeable and amino-thiocarbamated alginate (TSC) to prepare hybrid biosorbents (BVC-MSA). These ultralight and lyophilized phosphate rich macroporous sorbents were rationally characterized through FTIR, XRD, BET, SEM-EDS, elemental mapping, XPS techniques and employed for efficient UO22+ adsorption from aqueous solutions. The phytic acid (PA) was found to be a suitable hydrophilic and phosphorylating agent for the TSC matrix through hydrogen-bonded crosslinking when employed in a correct mass ratio (1:3). The SEM-EDS and XPS analyses confirmed the UO22+ sorption onto BVC-MSA-3 (the most suitable composite with a BVC/TSC mass ratio of 30.0 % w/w) and provided evidence of heteroatom involvement in developing the physico-chemical interactions. The BCV-MSA-3 exhibited the best response as a sorbent during kinetics/sorption process, therefore, it was selected to study the equilibrium sorption studies. The BCV-MSA-3 removal efficiency increased from 12.1 to 94.2 % using 0.2 to 1.8 g/L sorbent dose at pH (4.5). The mentioned sorbent displayed a significant maximum sorption capacity qm (309.55 mg/g at 35 °C) calculated through the best-fitted Langmuir and Temkin models (R2 ≈ 0.99). The sorption kinetics followed the pseudo-second-order (PSORE) model and exhibited fast sorption rate teq (180 min). Thermodynamic parameters clarified that the sorption process is feasible ΔGo (−25.3 to −27.6 kJ/mol kJ/mol), endothermic ΔHo (27.17 kJ/mol), and proceeds with a positive entropy (0.176 kJ/mol.K). The study shows that BCV-MSA-3 could be an alternative and auspicious sorbent for uranium removal from aqueous solution.

The novel performance and adsorption mechanism of synthesized modified zirconium-based metal-organic frameworks for resource recovery from wastewater

Phosphorous (P) is an indispensable nutrient popularly employed to fertilize agricultural farms. However, its overuse in farming leads to excessive discharge in agricultural runoff, causing eutrophication. To prevent harm to the environment, it is necessary to remove P from wastewater. Adsorption is one of the ways to achieve this goal. In this study, using a solvothermal process, UiO-66-NH2 was successfully modified/codoped with aluminum (Al) and magnesium (Mg). The Al/Mg-codoped UiO-66-NH2 was characterized using scanning electron microscopy, X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The study also investigated various adsorption factors, including temperature, pH, initial phosphate concentration, sorbent dosage, reaction time, and coexisting components. The findings demonstrated that the sorption process was predominantly based on chemical interactions, as evidenced by the Langmuir model (R2 > 0.99) and pseudo-second order (R2 > 0.99) analyses that fit well with experimental findings. The sorption capacity value was determined to be 117.6 mg P/g or 360.73 mg PO4/g. Thermodynamic results suggested the spontaneous and endothermic nature of P uptake process. Additionally, this research demonstrated the effective utilization of adsorbent for up to six regeneration cycles and recovery of adsorbed P using sodium hydroxide.

Removal of metaldehyde pesticide from aquatic media using modified cellulose obtained from Populus nigra plant, as potential adsorbent

Abstract In this study modified cellulose based adsorbent was prepared from Populus nigra plant, and used for elimination of metaldehyde (herbicide) from model waste water. The adsorbent was characterized through analytical technique such as FTIR, SEM, EDX and XRD for structural adsorption related parameters. The results of SEM showed the suitability of the material to be used as adsorbent and FTIR showed successful crosslinking of polyvinyl alcohol into cellulose structure. In order to get maximum reclamation benefits from adsorbent it was subjected to a number of tests evaluating the effect of metaldehyde concentration, sorbent dose, contact time, initial pH of solution and temperature. The maximum removal of 70 % was achieved under conditions of 80 mg/L metaldehyde concentration, 60 min contact time, pH of 8, 0.08 g sorbent dosage, and room temperature (25 °C). The Langmuir isotherm model with correlation coefficients of 0.9855 and maximum adsorption capacity recorded was 8.32 mg/g, while excellent agreement was shown by kinetic data with pseudo second order kinetic model with R 2 = 0.9876. Thermodynamic study indicated enthalpy change (ΔH° = −129 kJ/mol) to be negative, entropy change (ΔS° = 161.7 j/mol) positive, and the Gibbs free energy (ΔG) as negative showing that the process to be exothermic and feasible/spontaneous with an increase of randomness at solid liquid interface. The finding indicated that modified cellulose could be used as an efficient adsorbent for removal of metaldehyde from model waste water. However, further validation with other pollutants will be helpful in checking reproducibility of the present findings.

Characteristics of Removal of Lead, Cadmium and Chromium from Soil Using Biosorbent and Biochar

The study proposed the use of aspen wood sawdust and biochar derived from this sawdust for the removal of Pb(II), Cd(II), and Cr(VI) ions from soil in systems containing single metals as well as a mixture of all the studied metals. The effectiveness of the applied sorbents was compared with the sorptive properties of activated carbon. The results showed that all the tested materials reduced the metal content in the soil, and the obtained biochar was able to sorb lead, cadmium, and chromium ions in both studied systems. The influence of the type of sorbent, its dose, process duration, and the impact of metal on the removal efficiency and sorption capacity was analyzed. A statistical analysis of the obtained results was also conducted, determining the influence of process parameters on the removal capabilities of metal ions. The highest Pb, Cd and Cr ion removal efficiencies were obtained in a 36-day process at a sorbent dose of 10%. Aspen sawdust, biochar and activated carbon removed 46%, 50% and 71% of Pb(II), 35%, 43% and 53% of Cd(II) and 15%, 27% and 38% of Cr(VI), respectively. In turn, the highest sorption capacity values were achieved in a 36-day process at a sorbent dose of 2%, obtaining results of 20.2 mg/g, 22.3 mg/g and 23.2 mg/g of Pb(II), 5.1 mg/g, 7.9 mg/g and 11.7 mg/g of Cd(II) and 3.8 mg/g, 5.8 mg/g and 8.5 mg/g of Cr(VI), respectively. It was found that both raw aspen wood sawdust and biochar derived from this wood are effective in removing toxic metal ions from soil, which presents a potential solution to their presence in the natural environment.

Facile and efficient sequestration of uranium using biomass from Saudi Arabia’s local date palms waste

Kingdom of Saudi Arabia has announced to utilize its domestic resources to enhance its future nuclear power capacity to a total of 17.6 GW by 2040. This ambitious plan is followed by mining and extraction of uranium from various approaches both physically and chemically. Therefore, an economical and efficient approach was devised for harvesting uranium content from aqueous solutions by using two bio-sorbent, i.e., date pit sawdust (DPS) and date palm biowaste (PDB). The DPS and PDB were analyzed with BET surface area, FT-IR, SEM, EDX, pHPZC and XRD techniques to examine the surface area, porosity, functional group on surface, morphology, point of zero charge of the materials and nature of materials respectively. Effect of parameters like sorbent dose, solutions pH, concentrations and time of contact on adsorption were studied in a batch method. The findings indicated that both DPS and PDB exhibited significant sequestration of U(VI) with maximum adsorption observed at 6 pH. However, PDB exhibited the maximum sorption percentage (78.80 %) and capacity (3.25 mg/g), followed by DPS (70.5 %, 2.47 mg/g, respectively), for uranium sequestration.

Design and Production of Functionalized Electrospun Fibers for Palladium Recovery.

Adsorption stands out as a leading wastewater treatment method for ion removal or recovery. Polymeric fibers, notably electrospun ones, are gaining prominence due to their high capacity and easy recovery. Electrospinning offers a cost-effective means to produce fibers with a large surface area and high adsorption capacity. These fibers can be further functionalized with chemical substances acting as specific ligands for metal ions, bolstering their adsorption capabilities. In this study, dithioester-functionalized electrospun fibers were synthesized as an alternative to conventional sorbents for palladium recovery from acidic chloride solutions, similar to those used in hydrometallurgical processes for platinum group metal recovery (Pd, Pt, Rh···) from spent catalysts. Fibers with identical chemical composition but varying morphology were examined to assess their impact on palladium adsorption efficiency (i.e., beads-free and beads-on-string morphologies). Experimental investigations involved model solutions with varying palladium concentration, temperature, acidity (adjusted with HCl content), and salinity (adjusted with NaCl), utilizing both pure and dithioester-functionalized fibers. Experimental results demonstrate enhanced adsorption efficiency at lower temperatures and in 0.1 M HCl, with a negligible influence from solution salinity. Moreover, both pure polymeric and dithioester-functionalized electrospun fibers exhibit highly efficient palladium recovery. Furthermore, under optimal conditions, starting from an 80 mg/L palladium solution, a 95% recovery of palladium can be achieved with a sorbent dosage below 4 g/L of functionalized electrospun fibers. The adsorption data are well described by the Langmuir isotherm model for the pure polymeric fibers. At the same time, the contribution of dithioesters has been separately accounted for to describe the behavior of functionalized electrospun fibers. Thermal recovery of palladium from the spent sorbents has also been investigated.

Using Zeolite Materials to Remove Pharmaceuticals from Water.

Pharmaceutical drugs, including antibiotics and hormonal agents, pose a significant threat to environmental and public health due to their persistent presence in aquatic environments. Colistin (KOL), fluoxetine (FLUO), amoxicillin (AMO), and 17-alpha-ethinylestradiol (EST) are pharmaceuticals (PhCs) that frequently exceed regulatory limits in water and wastewater. Current removal methods are mainly ineffective, necessitating the development of more efficient techniques. This study investigates the use of synthetic zeolite (NaP1_FA) and zeolite-carbon composites (NaP1_C), both derived from fly ash (FA), for the removal of KOL, FLUO, AMO, and EST from aquatic environments. Batch adsorption experiments assessed the effects of contact time, adsorbent dosage, initial concentration, and pH on the removal efficiency of the pharmaceuticals. The results demonstrated that NaP1_FA and NaP1_C exhibited high removal efficiencies for all tested pharmaceuticals, achieving over 90% removal within 2 min of contact time. The Behnajady-Modirshahla-Ghanbary (BMG) kinetic model best described the adsorption processes. The most effective sorption was observed with a sorbent dose of 1-2 g L-1. Regarding removal efficiency, the substances ranked in this order: EST was the highest, followed by AMO, KOL, and FLUO. Sorption efficiency was influenced by the initial pH of the solutions, with optimal performance observed at pH 2-2.5 for KOL and FLUO. The zeolite-carbon composite NaP1_C, due to its hydrophobic nature, showed superior sorption efficiency for hydrophobic pharmaceuticals like FLUO and EST. The spectral analysis reveals that the primary mechanism for immobilizing the tested PhCs on zeolite sorbents is mainly due to physical sorption. This study underscores the potential of utilizing inexpensive, fly ash-derived zeolites and zeolite-carbon composites to remove pharmaceuticals from water effectively. These findings contribute to developing advanced materials for decentralized wastewater treatment systems, directly addressing pollution sources in various facilities.

Synthesis of high-ordered mesoporous aluminosilica monoliths using triblock copolymer and application in the water purification

Mesoporous aluminosilica particulates (MASP) offer a high surface area and specific structural properties that make them effective for adsorbing specific contaminants from drinking water. The MASP’s surface characteristics were studied by SEM, TEM, Mapping-EDX, and BET analysis. Through the use of a batch adsorption approach, this work sought to examine the adsorption behavior of MASP sorbent towards Cd(II) ions at different pH values, time intervals, sorbent doses, and temperatures. MASP’s maximal capacity for Cd(II) ions uptake was 16.5 mg/g at pH 6.5, 25 °C, 0.1 g dose, and 5 h of sorption time. The pseudo-first-order model provided a good description of the uptake process. The best-fitting isotherm was found to be the Langmuir and Redlich–Peterson isotherm. The method came out to be exothermic and spontaneous by thermodynamic analysis. MASP demonstrates durability and reusability during over ten regeneration cycles.

Enhanced capacity of thiol-functionalized sugarcane bagasse and rice husk biochars for arsenite sorption in aqueous solutions

The utilization of biowastes for producing biochar to remove potentially toxic elements from water represents an important pathway for aquatic ecosystem decontamination. Here we explored the significance of thiol-functionalization on sugarcane bagasse biochar (Th/SCB–BC) and rice husk biochar (Th/RH–BC) to enhance arsenite (As(III)) removal capacity from water and compared their efficiency with both pristine biochars (SCB–BC and RH–BC). The maximum As(III) sorption was found on Th/SCB–BC and Th/RH–BC (2.88 and 2.51 mg g−1, respectively) compared to the SCB–BC and RH–BC (1.51 and 1.40 mg g−1). Relatively, a greater percentage of As(III) removal was obtained with Th/SCB–BC and Th/RH–BC (92% and 83%, respectively) at a pH 7 compared to pristine SCB–BC and RH–BC (65% and 55%) at 6 mg L−1 initial As(III) concentration, 2 h contact time and 1 g L−1 sorbent dose. Langmuir (R2 = 0.99) isotherm and pseudo-second-order kinetic (R2 = 0.99) models provided the best fits to As(III) sorption data. Desorption experiments indicated that the regeneration ability of biochars decreased and it was in the order of Th/SCB–BC (88%) > Th/RH–BC (82%) > SCB–BC (77%) > RH–BC (69%) up to three sorption–desorption cycles. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy results demonstrated that the thiol (-S–H) functional groups were successfully grafted on the surface of two biochars and as such contributed to enhance As(III) removal from water. Spectroscopic data indicated that the surface functional moieties, such as -S–H, − OH, − COOH, and C = O were involved to increase As(III) sorption on thiol-functionalized biochars. This study highlights that thiol-grafting on both biochars, notably on SCB–BC, enhanced their ability to remove As(III) from water, which can be used as an effective technique for the treatment of As from drinking water.Graphical

Preparation and potential of chitosan-based/Al2O3 green hydrogel composites for the removal of methyl red dye from simulated solution.

Different dyes are discharged into water streams, causing significant pollution to the entire ecosystem. The present work deals with the removal of acid red 2 dye (methyl red-as an anionic dye) by green sorbents based on chitosan derivatization. In this regard, two classes of chitosan derivatives-a total of six-were prepared by gamma irradiation at 30kGy. The first group (group A) constitutes a crosslinked chitosan/polyacrylamide/aluminum oxide with different feed ratios, while the second group, identified as group B, is composed of crosslinked carboxymethyl chitosan/polyacrylamide/aluminum oxide with different ratios. Glycerol was added to soften the resultant hydrogels. The products were characterized by different tools, including FTIR for confirming the chemical modification, TGA for investigating their thermal properties, and XRD for verifying their crystalline structure. The morphology of the prepared derivatives was studied through SEM, while their topography before and after dye adsorption was monitored via the AFM. The removal efficiencies of the prepared sorbents were verified at different operation conditions, such as pH, temperature, adsorbent dose, initial concentration of dye solutions, and contact time. The data revealed that the optimum conditions for maximum dye uptake were as follows: pH 4, contact time 120min, 0.1-g sorbent dose, and 50-ppm dye concentration. Additionally, the prepared sorbents demonstrated potent adsorption capacity and removal efficiency. It was found that the elements of the second group displayed higher performance than their counterparts. The data showed also that the adsorption process best fits with the Freundlich model and obeyed pseudo-first-order kinetic isotherm. In addition, the synthesized composites showed observable antibacterial potency toward E. coli as a Gram-negative bacterium and S. aureus as a Gram-positive bacterium.