Adsorbent For Water Treatment Research Articles

Facial synthesis of colloidal stable magnetic nanoparticles coated with high hydrophilic negative charged poly(4‐styrenesulfonic acid co‐maleic acid) sodium for water remediation

AbstractThe enhancement of the colloidal stability of magnetite nanoparticles (MNPs) for environmental‐related fields has greatly attracted researchers' attention. This study used a high hydrophilic negatively charged polyelectrolyte, poly(4‐styrenesulfonic acid co‐maleic acid) sodium (PSAAS), to enhance the colloidal stability of MNPs. Coating of the naked MNPs with PSAAS polyelectrolyte is a simple and rapid method to obtain colloidally stable MNPs while sustaining the chemical reactivity of MNPs in water purification. The prepared PSAAS‐coated MNPs were characterized by scanning electron microscope, energy dispersive X‐ray, Fourier transform infrared, zeta potential analysis, transmission electron microscope and X‐ray diffraction. Moreover, the colloidal stability and adsorption performance tests of these naked MNPs and PSAAS‐coated MNPs (with different concentrations of PSAAS coated) were investigated and compared. PSAAS‐coated MNPs with 0.001 g/ml PSAAS coating possessed the best colloidal stability and the highest methylene blue (MB) dye removal efficiency (94.53 ± 0.69%). The adsorption isotherm and kinetic studies for the adsorption of MB onto PSAAS‐coated MNPs were well‐described by the Langmuir model and pseudo‐second‐order kinetic model. These magnetic adsorbents, with high separation efficiency, simple and low production cost and recyclable property, are promising as practicable adsorbents in water treatment.

Enhancing phosphate removal performance in water using La–Ca/Fe–LDH: La loading alleviates ineffective stacking of laminates and increases the number of active adsorption sites

Increasing the number of adsorption sites in layered bimetallic hydroxide (LDH), which is frequently used for phosphate removal in water, is a crucial step in enhancing phosphate adsorption. In this study, we investigate whether lanthanum (La) metal loading can improve the phosphate adsorption capacity of LDH. Based on Ca/Fe–LDH prepared through coprecipitation, a La–Ca/Fe–LDH composite is fabricated by La loading through impregnation. The adsorption capacity of La–Ca/Fe–LDH is 11.4% higher than that of Ca/Fe–LDH. The magnitude of adsorption and accelerated rate of adsorption of La–Ca/Fe–LDH satisfy the quasi-second-order kinetic and Langmuir isothermal equations. When comparing La–Ca/Fe–LDH to Ca/Fe–LDH, the adsorption capacity increased by 3.3%–328.39% in the pH range of 3–11; additionally, the resistance to pH influence and coexisting ion interference was considerably enhanced. However, under the coexistence of Cl−, NO3−, CO32−, SO42−, and F−, the adsorption capacity increased by 20.59%–27.6%. After three cycles of desorption, the phosphate removal abilit till increased by 11%, and the magnetic property was suitable for separation. The improvement of La–Ca/Fe–LDH adsorption capacity is attributed to the relief of ineffective stacking of LDH laminates and increased number of adsorption sites. The primary causes of adsorption are ion exchange, electrostatic attraction, and ligand exchange. In this study, a novel technique for enhancing LDH adsorption capability is proposed. This technique has numerous potential applications related to adsorbents in water treatment.

Fabricating Cationic Lignin Hydrogels for Dye Adsorption

Due to the low content of adsorption-active groups in lignin, its application in the field of adsorption is limited. Herein, we first prepared cationic kraft lignin acrylate, from which a cationic lignin (CKLA) hydrogel was further prepared by cationic kraft lignin acrylate, acrylamide, and N, N’-methylenebisacrylamide. The morphology, compression properties and swelling properties of CKLA hydrogels were investigated. The prepared CKLA hydrogel was applied as an adsorbent for Congo red. The effect of CKLA hydrogel dosages, initial concentration of Congo red, and pH on adsorption efficiency was investigated. The maximum Congo red removal efficiency was obtained at the initial concentration of Congo red of 50 mg/L, pH 7, and 5 mg dosage of CKLA hydrogel with 20% cationic lignin content. After five cycles of adsorption, the adsorption efficiency of the hydrogel for Congo red still reached more than 80%. The CKLA hydrogel showed pseudo-second-order adsorption kinetics for Congo red adsorption. These results demonstrate the potential of the CKLA hydrogel as an adsorbent for water treatment.

Biočađ i hidročađ kao adsorbenti za uklanjanje emergentnih zagađujućih materija iz otpadnih voda

Carbon materials have been used extensively in water treatment, and among them, biochar (BC) and hydrochar (HC) have been studied in recent decades as eco-friendly adsorbents in water treatment. Specific physicochemical characteristics of chars allow for the effective removal of a wide range of water contaminants, including emerging contaminants (e.g. pharmaceutically active compounds, agro-chemicals, and endocrine disrupting compounds). BC and HC can be synthesized from different biomass sources, even from biowaste, which makes them low-cost materials. In fact, the application of waste biomass for char production can be designated as a promising way towards achieving sustainable development goals concerning solid waste management. The selection of feedstock material and optimization of the reaction conditions of the carbonization process (pyrolysis, hydro-thermal carbonisation, etc.) influence the performances of char-based materials leading to the products with desired characteristics suitable for the removal of a certain group of compounds. The objective of this review is to provide an overview of the current status of research regarding the use of BC and HC as adsorbents in the removal of contaminants of emerging concern (CECs) from wastewater. The physicochemical properties of the substrates, types of synthesis, characterization techniques, as well as mechanism and influence of process parameters in the removal of selected CECs from wastewater, will also be addressed.

Uticaj strukture i hemijskog sastava celuloznog otpada na adsorpciju farmaceutika

In an attempt to reuse fibrous textile waste, and at the same time to reduce its quantity, waste hemp and flax fibers, and cotton yarn were used as cheap and sustainable adsorbents for the removal of pharmaceuticals from water. In order to improve their adsorption properties, waste fibers, and yarn samples were modified using 18% NaOH solution. Morphology, surface chemistry, and structural characteristics were examined through scanning electron microscopy, Fourier transform infrared spectroscopy, degree of surface crystallinity, and crystallinity index. Adsorption properties were analyzed through the determination of iodine sorption and water retention, as well as, the adsorption of selected sedatives. Modification with 18% NaOH increased the content of amorphous areas in examined fibers and yarn samples, improving their adsorption characteristics. Utilization of both unmodified and modified samples enables fast and highly efficient removal (adsorption efficiency ranging from 75 to 100%) of sedatives from water, making waste hemp and flax fibers and cotton yarn samples promising adsorbents for water treatment.

Multilayer films of graphene oxide and polymeric microgels: reusable adsorbents

Graphene oxide (GO) has arisen as an effective adsorbent for water treatment owing to its high removal efficiency for water pollutants. However, separating GO adsorbents from the pollutant solution is difficult after adsorption. The GO adsorbents are unsuitable for various dyes, and can only remove cationic dyes from an aqueous solution. To address these issues, this study utilized a simple and cost-effective layer-by-layer assembly technique to deposit multilayer films onto solid substrates. These films were composed of poly(allylamine hydrochloride)–dextran (PAHD) microgels and GO, and were designed to be highly effective while remaining affordable. The PAHD/GO multilayer films obtained produced an effortless separation process and demonstrated exceptional adsorption capabilities for cationic, anionic and non-ionic dyes. Specifically, the adsorption capacities for carmine and mulberry red were notably high, measuring 337.4 and 417.7 mg g−1, respectively. In addition, the PAHD/GO multilayer films could be regenerated well in sodium chloride solution without obvious compromise of removal efficiency. The adsorption kinetics, isotherms and thermodynamics of dyes on the PAHD/GO multilayer films were also studied. Thanks to the straightforward manufacturing process and outstanding adsorption capabilities of PAHD/GO multilayer films, this study presents a significant opportunity to advance the practical application of GO in water treatment.

Unique Mixture of (MgO-CdO) Nanoparticles as an Adsorbent for Water Treatment

Sol- gel method of synthesis of nanomaterials. Sol gel was applied for synthesis of magnesium oxide (MgO) and cadmium oxide (CdO) nanoparticles. Using magnesium nitrate and cadmium acetate as a raw materials and sodium hydroxide as a solvent for hydrated oxide at room temperature. Hydrated Magnesium oxide and cadmium oxide nanoparticles were annealed in air at 600 °C. The characterization methods include examine the morphology of the oxides surface using field emission scanning electron microscopy (FESEM) and Energy Dispersive X-ray spectroscopy (EDX), Characterization of functional groups was performed using Fourier Transform Infrared analysis (FTIR). X-ray powder diffraction (XRD) was used for examine the size of particles using Debye-Scherrer method. MgO and CdO nanoparticles are produced into spherical structures with average crystallite sizes of (55) and (55.5) nm, respectively. The study of using these nanoparticles as adsorbents were done successfully and the high value of removing percentage of iron about 97.8% and 98.7 respectively. Moreover, the mixture of these nano oxides gives 99.2% releasing of iron ion from polluted water.

Adsorption of Cadmium(II) Ions from Aqueous Solutions Using Calcium Molybdate

The presence of toxic metals in aquatic environments poses serious problems for ecosystems and especially for human health. Numerous types of metal oxides have been used to remove these metals and other toxic organic compounds, using adsorption systems. In this work, CaMoO4 was synthesized via coprecipitation and processed for different periods of time using a microwave-assisted hydrothermal system. It was possible to synthesize CaMoO4 on room temperature without any heat treatment. In addition, small processing times in HTMW were able to produce CM with different morphologies. The effect of the reaction time on the morphology of the product and particle size was examined in SEM images. A plausible CaMO4 formation mechanism was proposed based on time and temperature parameters. The potential application of CaMO4 as an adsorbent in water treatment was also investigated and this material exhibited a favorable adsorption performance in the fast removal of cadmium(ii) ions from aqueous solution of 1 mg L-1 concentration. So, CM showing a promising potential for use in environmental remediation.

Hotspots and Trends of Layered Double Hydroxide-based Adsorbents for Polluted Water Treatment: Insights from Bibliometric Analysis.

The use of layered double hydroxides (LDHs) as adsorbent for water treatment has been gaining relevance in recent years. In this context, this work aimed to map, through a bibliometric study, the extent of research that deals with the theme. The scientific database used was the Web of Science, and the chronology of the search consideredthe period from 1997 to 2022. The bibliometix R-package and VOSviewer software were used in this study. The searches retrieved a total of 663 documents, from 69 countries, distributed among all continents, which China (328), India (51) and Japan (40) were the most productive countries. Important journals in the environmental area and with high impact factor, such as Chemical Engineering Journal (44), Applied Clay Science (38), Journal of Hazardous Materials (35) and Chemosphere (27) most published in the area. The network of keywords used by the authors indicates that the publications retrieved deal mainly with aspects related to the efficiency of (LDHs) in the removal of different pollutants, the composition, the synthesis route and the association with other materials and/or techniques. The result of this study constitutes an important tool for directing future research on the subject.

Removal of Pb(II) ion by activated carbon synthesised from Musa Acuminate stem waste: surface properties, kinetics, adsorption mechanism, and reusability

ABSTRACT We present the synthesis of Activated Carbon (AC) by pyrolysis of Banana (Musa Acuminate) Stem Waste (BSW), and the ability of obtained AC for adsorptive removal of Pb(II) ions from water. Importantly, pyrolysis was performed at 750°C for 2.0 h in the presence of high surface area producing chemical activators such as NaOH, LiOH, H3PO4, ZnCl2, and KOH. BET-surface areas of AC produced with activators NaOH, LiOH, H3PO4, ZnCl2, and KOH were determined to be 908, 1531, 1670, 2245, and 2485 m2 g−1, respectively. Pore volume ascending order was determined as 0.59 (NaOH) < 0.68 (LiOH) < 0.86 (H3PO4) < 0.97 (ZnCl2) <1.18 (KOH) cm3 g−1. SEM and TEM images revealed the porous nature of the ACs. ACs produced with H3PO4, ZnCl2, and KOH exhibit type I adsorption isotherms, indicating their microporous nature. ACs prepared with NaOH and LiOH exhibit type II adsorption isotherms, indicating their macroporous nature. X-ray diffraction, X-Ray photoelectron, and Raman spectroscopy analysis revealed the graphitic structure of ACs. Pb(II) ion adsorption onto ACs surface obeyed the Langmuir model. It was found that the Pb(II) adsorption capacities of the ACs produced with NaOH, LiOH, H3PO4, ZnCl2, and KOH as the chemical activators were 220, 283, 326, 329, and 435 mg g−1, respectively, at the optimised conditions (pH = 6.6, contact time = 100 min, [ACs] = 0.125 g L−1, at 30°C). The interaction between surface functional groups of ACs and Pb(II) ions was confirmed by X-Ray photoelectron and FT-Infrared spectroscopy. The negative values of ΔGo and ΔHo reveal that the Pb(II) ion adsorption onto the ACs surface is spontaneous and exothermic. The Pb(II) ion adsorption capacity increased with an increase in BET-SA and pore volume of ACs, with AC obtained from BSW with KOH exhibiting the highest adsorption capacity of 435 mg g−1. Thus, the study highlights BSW, agricultural biomass waste is a low-cost and abundantly available carbon precursor to synthesise potential AC adsorbent for water treatment.

Waste-Coffee-Derived Activated Carbon as Efficient Adsorbent for Water Treatment.

Activated carbon prepared from waste coffee was utilized as a potential low-cost adsorbent to remove Rhodamine B from aqueous solution. A series of physical characterizations verify that the obtained activated carbon possesses a layered and ordered hexagonal structure with a wrinkled and rough surface. In addition, high specific surface area, appropriate pore distribution, and desired surface functional groups are revealed, which promote the adsorption properties. Various adsorption experiments were conducted to investigate the effect on the absorption capacity (e.g., of initial dye concentration, temperature and solution pH) of the material. The results showed that the waste-coffee-derived activated carbon with a large surface area of approximately 952.7 m2 g-1 showed a maximum uptake capacity of 83.4 mg g-1 at the pH of 7 with the initial dye concentration of 100 mg L-1 under 50°C. The higher adsorption capacity can be attributed to the strong electrostatic attraction between the negatively charged functional groups in activated carbon and the positively charged functional groups in RB. The kinetic data and the corresponding kinetic parameters were simulated to evaluate the mechanism of the adsorption process, which can fit well with the highest R2. The adsorption results confirmed the promising potential of the as-prepared waste-coffee-derived activated carbon as a dye adsorbent.

Synthesis of g-C3N4/ZnO/WO3 nanocomposite as a highly efficient antibacterial adsorbent for water treatment

The design of highly efficient adsorbents for the extraction of dye molecules from wastewater is currently in great demand due to the widespread of polluted water. A simple in-situ procedure was utilized to produce a ternary g-C 3 N 4 /ZnO/WO 3 nanostructure composite that exhibits strong and fast adsorption properties for the removal of methylene blue. In addition, the antibacterial characteristics of produced ternary samples were studied. Adsorption measurements were taken in a systematic manner to examine the effects of initial methylene blue concentrations, the composition of samples, contact time temperature, adsorbent amount, and pH value on dye removal. The results showed that the ternary g-C 3 N 4 /ZnO/WO 3 composite adsorb more than 98 % of dye below 5 min. Although the surface area of the samples was reduced after making a ternary composite, the dye adsorption dramatically increased. The synergistic impact of g-C 3 N 4 , ZnO, and WO 3 , which creates the active sites, is largely responsible for powerful adsorption. Thermodynamic parameters of the synthesized samples were measured. The synthesized samples also showed good antibacterial characteristics against both Escherichia coli , and Staphylococcus aureus bacteria. • A simple procedure was utilized to produce g-C 3 N 4 /ZnO/WO 3 nanocomposite. • The synergistic impact of g-C 3 N 4 , ZnO, and WO 3 created powerful adsorption. • The samples showed good antibacterial characteristics. • Thermodynamic parameters of the adsorption were also investigated.

Ecofriendly and low-cost bio adsorbent for efficient removal of methylene blue from aqueous solution

A novel bio adsorbent was fabricated from turmeric, polyvinyl alcohol and carboxymethyl cellulose for MB dye removal. The physicochemical, antibacterial and biodegradable nature of the film was evaluated using scanning electron microscopy, optical microscopy, universal testing machine, water contact angle, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, agar disc diffusion method and soil degradability. The inclusion of turmeric into PVA/CMC film improves the biodegradability, antibacterial activity and thermomechanical property of the films. PVA/CMC/TUR film displayed good MB adsorption capacity (qe: 6.27 mg/g) and maximum dye adsorption (R%; 83%) and was achieved at initial dye concentration of 10 mg/L with contact time 170 min at room temperature. The adsorption data of MB on PVA/CMC/TUR film was evaluated using four models Langmuir, Freundlich, Temkin and D-R isotherms. The different kinetic of adsorption (pseudo-first order, pseudo-second order and intraparticle diffusion model) was also applied for adsorption of MB on the films. The experimental result suggests that PVA/CMC/TUR films are an alternate cheap adsorbent for water treatment.

A Crosslinked Ionic Organic Framework for Efficient Iodine and Iodide Remediation in Water.

Iodine is widely used as an antimicrobial reagent for water disinfection in the wilderness and outer space, but residual iodine and iodide need to be removed for health reasons. Currently, it is challenging to remove low concentrations of iodine and iodide in water (≈5 ppm). Furthermore, the remediation of iodine and iodide across a broad temperature range (up to 90 °C) has not previously been investigated. In this work, we report a nitrate dimer-directed synthesis of a single-crystalline ionic hydrogen-bonded crosslinked organic framework (HC OF-7). HC OF-7 removes iodine and iodide species in water efficiently through halogen bonding and anion exchange, reducing the total iodine concentration to 0.22 ppm at room temperature. Packed HC OF-7 columns were employed for iodine/iodide breakthrough experiments between 23 and 90 °C, and large breakthrough volumes were recorded (≥18.3 L g-1 ). The high iodine/iodide removal benchmarks recorded under practical conditions make HC OF-7 a promising adsorbent for water treatment.

A Crosslinked Ionic Organic Framework for Efficient Iodine and Iodide Remediation in Water

AbstractIodine is widely used as an antimicrobial reagent for water disinfection in the wilderness and outer space, but residual iodine and iodide need to be removed for health reasons. Currently, it is challenging to remove low concentrations of iodine and iodide in water (≈5 ppm). Furthermore, the remediation of iodine and iodide across a broad temperature range (up to 90 °C) has not previously been investigated. In this work, we report a nitrate dimer‐directed synthesis of a single‐crystalline ionic hydrogen‐bonded crosslinked organic framework (HCOF‐7). HCOF‐7 removes iodine and iodide species in water efficiently through halogen bonding and anion exchange, reducing the total iodine concentration to 0.22 ppm at room temperature. Packed HCOF‐7 columns were employed for iodine/iodide breakthrough experiments between 23 and 90 °C, and large breakthrough volumes were recorded (≥18.3 L g−1). The high iodine/iodide removal benchmarks recorded under practical conditions make HCOF‐7 a promising adsorbent for water treatment.

A feasible strategy for separating oxyanions-loaded microfine Fe-MOF adsorbents from solution by bubble flotation

Microfine metal–organic frameworks (MOFs) are promising adsorbents for water treatment, but their commercial applicability is severely constrained by poor separability. Herein, we designed a feasible bubble flotation strategy for achieving the effective separation of oxyanions-loaded Fe-MOF particles in the solution after adsorption, by modifying the particle interface properties and introducing bubbles mineralization. The results showed that the separation of P(V), Mo(VI) and W(VI) oxyanions-loaded Fe-MOF could be completely achieved under optimum conditions. FTIR, XPS and DFT analyses revealed that the particle size and hydrophobicity of oxyanions-loaded Fe-MOF increased by sodium dodecyl sulfate (SDS) collector via chemisorption and electrostatic interactions. The collision and attachment models analysis of bubbles with particles demonstrated that the separation efficiencies of collector modified oxyanions-loaded Fe-MOFs were significantly enhanced with increasing bubble mineralization. EDLVO theoretical calculations and bubble-particle carrying ability analysis demonstrated that the gravitational interactions between oxyanions-loaded Fe-MOF particles and particles/bubbles were intensified by the collector. The gravitational interaction further induced particle aggregation and enhanced the carrying capacity of individual bubbles. This work provides a feasible strategy for the removal of oxyanions and the separation of oxyanions-loaded microfine Fe-MOF in the adsorption process.

Cellulose/polyaniline hybrid nanocomposites: Design, fabrication, and emerging multidimensional applications

Polyaniline, a special class of intrinsic conducting polymers, has a wide range of potential applications in multiple fields, such as in biosensors, electronics devices and biomedical applications. Polyaniline possesses high electrical conductivity, low toxic contents, hydrophilic character, better environmental stability and nanostructured surface characteristics. Polyaniline has however a current limited set of applications because of its low degradation rate and poor processibility; for this reason, polyaniline has been blended with different nano/micro cellulosic biomaterials (i.e. cellulose nano crystals and nano fibers, bacterial cellulose and macro cellulose). Furthermore, cellulose-reinforced polyaniline matrices have shown significant potential for antibacterial agents, antioxidants, sensors, electromagnetic shielding device, adsorbent in water treatment, fuel cells, electrochromic and in biomedical applications. These biodegradable and environmentally benign conducting polymers have also been used in tissue engineering, biosensors, and drug delivery. In the present review article we have surveyed recent advancements in the synthesis process and progress of polyaniline/cellulose based bio-composites for water treatment, electrical devices, biosensors, biomedical application and other areas. The article aims at providing a comprehensive background on the topic, as well as at proposing innovative strategies among investigators for the use of these biobased polymers in future work. The various factors and conditions that impact the adsorption/deterioration behavior of cellulose/PANI composites during the removal of heavy metals, dyes, and other effluents from waste water have also been discussed. Additionally, a comparative view of various fuel cells, electrochromic devices and the electrical and magnetic properties of different cellulose/polyaniline composites has also been provided. • Synthesis and structure of physico-chemical properties of Polyaniline (PANI). • Benefits of blending polyaniline with cellulose. • PANI nanocomposites role in water purification and gas sensing. • Development of electrochromic, fuel cells and electromagnetic shielding devices. • Remarkable potential of PANI-based nanocomposites for bio-medical applications.

Hyperbranched polyamidoamine-chitosan polyelectrolyte gels crosslinking by polyacrylic acid and alginate for removal of anionic dyes

Difficult-to-treat wastewater discharged from printing and dyeing industries has posed an environmental risk. Three-dimensional porous structures exhibit excellent dye adsorption properties. In this study, chitosan (CTS) was introduced in situ on polyamidoamine (PAMAM). Then, the composite gels containing sodium alginate (SA)/CTS in situ grown on PAMAM/polyacrylic acid (SCPP-Gn (n = 0,1,2,3)) were prepared with a controllable structure using a semi-dissolution acidification sol-gel transition method (SD-A-SGT). Owing to the stronger mechanical strength and larger specific surface area, the SCPP-G2 composite gel has the higher stability and the greater adsorption capacity for dyes, with maximum adsorption capacities of 325.21 mg/g for rose bengal (RB) and 222.40 mg/g for sunset yellow (SY). The mechanism study showed that the adsorption toward RB and SY was dominated by chemical adsorption. After five adsorption-desorption cycles, it was found that 70 % of the initial adsorption capacity could be retained. Our study demonstrates the great potential of the SCPP-G2 composite gel as an adsorbent in water treatment.

Comparative life cycle assessment of activated carbon production from various raw materials

Activated carbon (AC) is an effective adsorbent in water treatment but its production method has significant emissions to the environment. This study aims to quantify the environmental impacts of various AC types and determine whether raw material selection could reduce the footprint of AC. A cradle-to-gate life cycle assessment (LCA) was conducted on coal, coconut shell, wood, peat, and reactivated coal ACs. The different types of raw materials were selected to reflect typical global and local availability in the selected location. Life cycle data was collected from the Ecoinvent database, scientific literature, and an industrial producer. Using CML 2001 as a characterization method, potential environmental impacts were calculated for 12 categories. The direct emissions of AC production and electricity production were the largest contributors to environmental impacts. Coal AC had the highest impact in ten out of the twelve categories. On the other hand, reactivated coal and coconut AC had the lowest impacts in three and five categories, respectively. The comparison in carbon footprints between the AC types were found to be dependent on inclusion or exclusion of biogenic emissions: When including biogenic carbon emissions, the Global Warming Potential (GWP) of reactivated coal AC was 72–80% lower than for the virgin ACs. When biogenic carbon emissions were excluded, the GWPs of the residual biomass ACs (coconut shell and wood) were found to be about 50% lower than that of reactivated coal AC. The results demonstrate that raw material choice and production method significantly affect the environmental impact of AC. To minimize site-specific impacts of AC application, technical feasibility of AC and use phase emissions need to be assessed.

Effectiveness and mechanisms of the adsorption of carbendazim from wastewater onto commercial activated carbon.

The wide application of fungicides is becoming one of the main causes of water pollution. Activated carbon (AC) is a frequently-used adsorbent in water treatment. In this work, aiming to obtain a better understanding of fungicides on AC, carbendazim was selected as a model fungicide in water. The effects of AC dosage, adsorption temperature, adsorption time and pH value of solution on carbendazim adsorption by AC were investigated. When the initial concentration of carbendazim was 500mgL-1 and the volume of wastewater was 25mL, the optimum dosage of AC and reaction time was determined to be 0.3g and 150min, respectively. The pH ranging from 3.0 to 10.0 exhibited little effect on the adsorption capability of AC. The higher the adsorption temperature was, the better adsorption capacity was. Adsorption capacity could reach 32.31mgg-1 under the optimal adsorption conditions. The kinetics study reveals that the adsorption of carbendazim occurred on the surface of adsorbent during initial stage. The adsorption data was well fitted by Langmuir adsorption isotherm, indicating that the adsorption process was monolayer adsorption. The thermodynamic experiments confirmed that the adsorption of carbendazim was an endothermic process with the coexistence of physical and chemical adsorption. Because the main components of AC used in this research work is amorphous carbon with low impurity and its surface has not been modified with additional functional groups, the conclusion of the study was easy to be replicated by repeated experiments. Therefore, the findings of this study could guide the adsorption of carbendazim onto the other kinds of AC with high specific surface area, and provide useful information for application of commercial AC in treatment of fungicides wastewater.