Adsorbent For Removal Research Articles

Rapid adsorptive removal of congo red using Cu/Fe/Al mixed metal oxides obtained from layered double hydroxide nanomaterial: Performance and optimization evaluation using BBD-RSM approach

This work utilized a one-pot synthesis method to synthesize Cu/Fe/Al mixed metal oxide (MMO) from layered double hydroxide (LDH) calcination. The adsorption potentials of Cu/Fe/Al LDH and Cu/Fe/Al MMOs were evaluated using Congo Red (CR) aqueous solution. Various advanced techniques were used to characterize the synthesized nanomaterial. XRD confirmed the successful synthesis of trimetallic carbonate intercalated LDH and MMO, while FE-SEM revealed their flaky morphology. EDX and FT-IR analyses supported the dye removal mechanism, showing that MMOs had greater adsorptive removal of CR molecules than LDH. This was primarily due to the MMOs' larger surface area and microporous structure (132 m²/g) which favoured greater adsorption. The adsorption kinetics reveal that the adsorptive removal of CR on LDH and MMOs follows a pseudo-second-order reaction. Moreover, as predicted by Freundlich the maximum adsorptive removal was obtained by LDH-derived MMO (96%) which was higher than the LDH (90%). The thermodynamics indicates that adsorption was exothermic and thus more favorable at room temperature. In addition, the Box-Behnken Design (BBD) was adopted for Response Surface Methodology (RSM) due to its simplicity in analysis and effectiveness in systematically evaluating the impact of pH, dosage of adsorbent, dye concentration, contact period, and temperature variables. The pHzpc of 7.9 indicated that lower pH enhances adsorption, and a +5.1 mV charge on the MMO surface, measured by zeta potential, supported electrostatic interaction with the anionic dye. Lastly, LDH and LDH-derived MMO were regenerated using 1 M NaOH and effectively reused for up to 5 cycles. MMOs demonstrated superior reusability compared to LDH for anionic dye removal. Thus, the synthesised Cu/Fe/Al MMO, with its large surface area, offers a superior adsorbent for removing organic pollutants.

Adsorptive Removal of Dyes: A Comparison of Graphene Oxide to Granular Activated Carbon and Zeolite NaY

Synthetic carbon-based compounds are a prevalent wastewater contaminant that can adversely impact water resources due to their potential carcinogenic and toxic effects on aquatic biota and human health. This research investigates the versatility of graphene oxide (GO) as an alternative to commonly used adsorbents (zeolite NaY (NaY) and granular activated carbon (GAC)) for removal of synthetic cationic dyes. Rhodamine B (RhB) and methylene blue (MB), were selected as the target contaminants to represent cationic synthetic dyes with differing molecular sizes and structural compositions. Batch experiments using GO, NaY, and GAC as adsorbents were used to assess both physicochemical interactions between adsorbent surfaces and contaminants, and removal efficiency. GO demonstrated the highest removal efficiency for both target contaminants—at 99% and 86%, respectively—while the lowest removal efficiency was observed for NaY. Langmuir, Freundlich, Temkin, and BET isotherm models were used to describe the adsorption isotherms. Overall, GO demonstrated a more robust and higher removal efficiency of cationic dyes compared with GAC and NaY, indicating the potential of graphene oxide for the removal of complex structured organic contaminants in wastewater treatment.

Preparation of Composites Derived from Modified Loess/Chitosan and Its Adsorption Performance for Methyl Orange.

A modified loess/chitosan composite (ML@CS) was prepared via solution. The microstructure and physicochemical properties of ML@CS were characterised via scanning electron microscope (SEM), Zeta potential, X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), and thermogravimetric analysis (TGA). An aqueous solution of methyl orange (MO) was used as simulated wastewater from which the influence of the initial concentration and pH of MO, the dosage amount and regeneration performance of ML@CS, adsorption temperature, and time on the adsorption effect of MO were systematically investigated. The adsorption kinetics, isothermal adsorption, and adsorption mechanism were also analysed. The results indicate that ML@CS had a good adsorption effect on MO. When the initial concentration of MO was 200 mg/L, pH was 5.0, and ML@CS dosage was 1.0 g/L, the adsorption equilibrium could be reached within 180 min at room temperature, and the equilibrium adsorption capacity and removal rate reached 199.52 mg/g and 99.75%, respectively. After five adsorption-desorption cycles, the MO removal rate remained above 82%. The adsorption behaviour of ML@CS for MO conforms to the pseudo-second-order kinetic model and the Langmuir isotherm adsorption model. The spontaneous exothermic process was mainly controlled by monolayer chemical adsorption and the physical adsorption only played an auxiliary role. ML@CS efficiently adsorbed MO in water and can be used as a high-efficiency, low-cost adsorbent for printing and dyeing wastewater treatment.

Adsorptive Removal of Bisphenol A by Polyethylene Meshes Grafted with an Amino Group-Containing Monomer, 2-(Dimethylamino)ethyl Methacrylate

The adsorptive removal of Bisphenol A (BPA) with the PE meshes photografted with 2-(dimethylamino)ethyl methacrylate (DMAEMA) was performed by varying the grafted amount, pH value, BPA concentration, and temperature, and the adsorption performance was correlated by the equilibrium, kinetic, and isotherm models. In addition, the regeneration of DMAEMA-grafted PE (PE-g-PDMAEMA) meshes was discussed from the repetitive adsorption/desorption process. The adsorption capacity had the maximum value at the grafted amount of 2.6 mmol/g and at the initial pH value of 8.0. The increase in the protonation of dimethylamino groups on grafted PDMAEMA chains and the dissociation of phenol groups of BPA present in the outer solution during the adsorption process results in the increase in BPA adsorption. The adsorption process followed the pseudo second-order equation. The BPA adsorption was enhanced by increasing the BPA concentration and the equilibrium data fit to Langmuir equation. The adsorption capacity stayed almost constant with the increase in the temperature, whereas the k2 value increased against the temperature. These results comprehensively emphasized that BPA adsorption occurred through the chemical interaction or ionic bonding of a BPA anion to a terminal protonated dimethylamino group. Desorption of BPA increased by increasing the NaOH concentration and BPA was entirely desorbed at more than 20 mM. The cycle of adsorption at pH 8.0 and desorption in a NaOH solution at 100 mM was repeated five times without loss or structural damage. These results indicate PE-g-PDMAEMA meshes can be used as a regenerative adsorbent for BPA removal from aqueous medium.

Bio-Graphene Foam: A Robust Solution for Adsorptive and Sustainable Chlorophenol Removal from Wastewater

Bio-Graphene Foam: A Robust Solution for Adsorptive and Sustainable Chlorophenol Removal from Wastewater

Preparation, characterization and application of polymeric ultra-permeable biodegradable ferromagnetic nanocomposite adsorbent for removal of Cr(VI) from synthetic wastewater: kinetics, isotherms and thermodynamics

Hexavalent chromium (Cr(VI)) contamination in drinking water due to industrial activities is a growing worldwide concern. Cr(VI) concentrations exceeding a few parts per billion (ppb) can cause serious health problems such as asthma, blood cancer, kidney-related diseases, liver and spleen damage, as well as neurological system, immunological deficiencies, and reproductive issues. This study, thus, explored the feasibility of employing a novel polymeric ferromagnetic nanocomposite adsorbent made of low-cost, biodegradable, and ultra-permeable materials from pulp and paper sludge for adsorptive removal of hexavalent chromium (Cr6+) from synthetic wastewater. Vibrating-sample magnetometer (VSM), X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmet-Teller surface area (BET), and Fourier transform infrared (FTIR) were used to analyze the produced nanocomposite adsorbent. The Fourier transform infrared results confirmed the presence of adsorptive peaks attributed to −OH, −NH2, and FeO. Scanning electron microscopy micrographs revealed a porous adsorbent surface. XRD revealed the existence of the crystalline spinel-structured magnetite (Fe3O4) phase of iron oxide, while the saturation magnetization was established to be 26.90 emu/g. The Brunauer–Emmett–Teller analysis confirmed a slight decrease in the surface area of the nanocomposite adsorbent to 6.693 m2.g−1, compared to Fe3O4 (7.591 m2.g−1). The optimum conditions for Cr6+ removal were pH 2.0, 1.0 g/L adsorbent dose, room temperature (25°C), 120 min contact time, and 20 mg/L pollutant concentration. During removal, the Cr(VI) was adsorbed by electrostatic attraction and/or reduced to trivalent chromium Cr(III). At low starting Cr(VI) concentrations, chemisorption dominated the removal process, but as concentrations increased, physisorption became more significant. The prepared nanocomposite adsorbent presented exceptional removal efficiency of up to 92.23%, indicating that it may be useful for the adsorption of metal ions from industrial and household wastewater.

Highlighting the adsorption mechanism of a fluoroquinolone antibiotic from wastewater on carbon xerogel by experiments, characterization, modelling and DFT simulation.

The application of a synthesized carbon xerogel (RFX) for the adsorptive removal from water of ciprofloxacin (CPX), a widely used fluoroquinolones-group antibiotic for humans and animals, has been reported in this work. The carbon xerogel was characterized by N2 adsorption-desorption isotherms, FTIR, Raman spectroscopy, TPD studies, elemental analysis, determination of isoelectric point (pHIEP) and scanning electron microscopy (SEM). CPX adsorption experiments were conducted in batch mode, using results obtained with F400 commercial activated carbon for comparison purposes. CPX adsorption kinetics were well-described by the pseudo-second-order model for both adsorbents and by the Elovich model in the case of F400 activated carbon. Therefore, CPX equilibrium adsorption capacity values were of 457 and 72mgg-1 for RFX xerogel and F400 activated carbon, respectively. This significant difference can be attributed to the higher specific surface area and micropores volume values of F400 carbon; in this sense, this material led to a slower CPX kinetic adsorption. Also, the Dual-site Langmuir model best-described the experimental CPX adsorption isotherms in both cases. By the adsorption studies at different solution pH, it could be concluded that several mechanisms, e.g., hydrophobic and π-π interactions, and electrostatic forces highly influenced CPX adsorption capacity. Furthermore, adsorption tests using several environmentally relevant aqueous matrices have been accomplished. In this case, a competitive effect between the natural organic matter (NOM) and the target pollutant occurred in all the tested real matrices, decreasing CPX adsorption capacity, especially remarkable for F400 activated carbon. Finally, Density Functional Theory (DFT) has been used to elucidate the interactions between CPX and adsorbents, finding a high relevance of the π-π electron donor-acceptor interactions in which CPX acts as an acceptor.

Adsorption Isotherm and Removal Efficiency. How Are They Related?

Adsorption Isotherm and Removal Efficiency. How Are They Related?

Multifunctional property of N,N-bis (carboxymethyl) glutamic acid modified biomass material: adsorption and degradation removals of cationic dyes in wastewater

As a common type of pollutants in industrial wastewater, cationic dyes have attracted great attentions. Using biodegradable N,N-di (carboxymethyl) glutamic acid (GLDA) as ligand and corn stalk (CS) as matrix, a novel and green biomass modified material GLDA-CS was successfully prepared. The multifunctional property of GLDA-CS for removing methylene blue (MB), malachite green (MG) and alkaline red 46 (R-46) from wastewater was evaluated. The dyes were removed by the electrostatic adsorption based on the cationic adsorption properties of GLDA-CS. The removal rates of MB, MG and R-46 can quickly reach 90.4%, 96.8% and 94.8% in short time. especially for MG and R-46 even only 20 min. The adsorption capacities of the dyes still remain more than 86.5% of the initial values after 5 cycles. In a heterogeneous system, the dyes were removed by Fenton-like degradation based on the metal chelating property of GLDA-CS. 100% degradation rates of the dyes can be achieved in 35 min under the acidic region. Even if at pH 7, degradation rates are 44.1%, 47.1% and 56.6% higher than those under the conventional homogeneous system, and the degradation rate remained at 83.7% after 5 cycles. Regardless of the adsorption or degradation, GLDA-CS shows strong anti-anion interference ability. The potential mechanisms of adsorption and degradation for the dyes by GLDA-CS were deduced by quantization calculation. It is concluded that the adsorption removal of the dyes by GLDA-CS follows MG > R-46 > MB, and mainly depends on the electrostatic interaction between -COOH in GLDA-CS and -N- in the dye molecules. Based on the degradation mechanism of Fenton-like reaction, the possible active sites of the dyes attacked by free radicals and their possible degradation intermediates were predicted by the calculations of Fukui function.

The Influence of Thermal Treatment of Activated Carbon on Its Electrochemical, Corrosion, and Adsorption Characteristics

Activated carbons can be applied in various areas of our daily life depending on their properties. This study was conducted to investigate the effect of thermal treatment of activated carbon on its properties, considering its future use. The characteristics of activated carbon heat-treated at temperatures of 1500, 1800, and 2100 °C based on its future use are presented. The significant effect of the treatment temperature on morphological, adsorption, electrochemical, and corrosion properties was proved. Increasing the temperature above 1800 °C resulted in a significant decrease in the specific surface area (from 969 to 8 m2·g−1) and material porosity—the formation of mesopores (20–100 nm diameter) was observed. Simultaneously, adsorption capability, double layer capacity, and electrochemically active surface area also decreased, which helped to explain the shape of cyclic voltammograms recorded in 2,4-dichlorophenoxyacetic acid and in supporting electrolytes. However, a significant increase in corrosion resistance was found for the carbon material treated at a temperature of 2100 °C (corrosion current decreased by 23 times). Comparison of morphological, adsorption, corrosion, and electrochemical characteristics of the tested activated carbon, its applicability as an electrode material in electrical energy storage devices, and materials for adsorptive removal of organic compounds from wastewater or as a sensor in electrochemical determination of organic compounds was discussed.

Enhanced adsorption of aqueous perfluorooctanoic acid on iron-functionalized biochar: elucidating the roles of inner-sphere complexation

Perfluorooctanoic acid (PFOA) is ubiquitously detected in various water bodies, which raises the urgent need for developing effective and economic remediation methods in response to its health risks. The adsorptive removal of PFOA by biochar (BC) is regarded as a simple, effective, and economical technique. However, engineered BCs, including FeCl3-activated BC, for PFOA removal and adsorption mechanisms have been ill-studied. In this study, a FeCl3-activated dairy manure-derived biochar (Fe@MBC) was prepared via one-step pyrolysis/activation, and its properties and adsorption characteristics were compared with a pristine manure-derived biochar (P-MBC). The FeCl3 activation largely increased the surface area of Fe@MBC and the deposition of FexOy minerals on surface of Fe@MBC while significantly elevating the surface roughness of Fe@MBC. The maximum adsorption capacity of Fe@MBC for PFOA (233 mg·g−1) was five times higher than that of P-MBC (46 mg·g−1). PFOA adsorption was favorable at low solution pH and was independent on ionic strength, which supported the major contribution by inner-sphere complexation rather than out-sphere complexation. This mechanism was further confirmed by the disappearance of FeO peak on Fourier transform infrared spectrum and the blue-shift of Fe binding energies on X-ray photoelectron Fe 2p spectrum of Fe@MBC after PFOA adsorption. Fe@MBC maintained a near 100% adsorption capacity for PFOA after 4 cycles of chemical regeneration. Fe@MBC also exhibited efficient removal for PFOA and other PFAS compounds at trace levels in the lake water and wastewater treatment plant effluent. Thus, this study highlights a promising insight for selectively eliminating PFASs from water.

Biosorption of Pb(II) Ions through Nanostructured Teff Straw based Magnetized Activated Biocarbon: Aspects on Modeling, Optimization, and Kinetics

<p>In this study, activated carbon (AC) was prepared from teff grass straw via chemical activation and microwave-assisted pyrolysis. The AC was modified by magnetization followed by it was characterized by particle size, FTIR, XRD, thermogravimetric study, pore size, and magnetic properties. Further, it was evaluated for its adsorptive removal performance of lead (II) ions from aqueous solution. A statistical model was developed by response surface method (RSM) and the crucial parameters, concentration of initial Pb(II), biosorbent loading, solution pH, and contact time were optimized for maximizing the adsorption of Pb(II) ions. The optimal values were 95.36 mg/L, 0.656 g/100 mL, 5.5, and 88.7 min, respectively for aforementioned parameters. Under the optimal condition, the Langmuir isotherm exhibited the most accurate correspondence with the obtained experimental data. The findings from the kinetic analysis were found to be statistically fit to the pseudo-2nd order model.</p>

Using syringe filtration after lab-scale adsorption processes potentially overestimates PFAS adsorption removal efficiency from non-conventional irrigation water.

The adsorption process, known for its cost-effectiveness and high efficiency, has been extensively investigated at the laboratory scale for removing per- and polyfluoroalkyl substances (PFAS) from non-conventional irrigation water. However, a syringe filtration step is commonly used when quantifying PFAS removal during this adsorption process, potentially leading to PFAS retention onto the filters and an overestimate of adsorption removal efficiency. Here, we assessed the retention of three prevalent PFAS (i.e., perfluorooctanoic acid [PFOA], perfluorooctane sulfonic acid [PFOS], and perfluorobutanoic acid [PFBA]) on six syringe filters. When filtering distilled deionized water spiked with 1µg/L and 100µg/L of each PFAS, we observed the highest and lowest PFAS recovery percentages by mixed cellulose ester (MCE) (0.20µm, 25mm; 97±11%, 101±4.8%) and polytetrafluoroethylene (0.45µm, 13mm; 61±37%, 80±28%), respectively. Under the initial concentration of 1µg/L and 100µg/L, PFOS had recovery percentages of 55±25% and 68±24%, significantly lower than 96±12% and 99±5% for PFOA and 95±8% and 97±4% for PFBA, highlighting the importance of PFAS functional groups. PFAS recovery percentage increased with filtration volume in the order of 80±28% (1mL)<85±21% (5mL)<90±18% (10mL). Using MCE to filter treated municipal wastewater spiked with 1µg/L and 100µg/L of each PFAS, we found recovery percentages>90% for all three PFAS. Our study underscores the significance of syringe filter selection and potential overestimate of PFAS removal efficacy by the lab-scale adsorption processes.

Adsorption isotherms and removal of lead (II) and cadmium (II) from aqueous media using nanobiochar and rice husk

Removal of Cd(II) and Pb(II) from aqueous solutions is a challenging task and the search for novel adsorbents is underway. This study examined the efficiency of nanobiochar (NB) and rice husk (RH) in the adsorption and removal of Cd(II) and Pb(II) from water. The effect of various physicochemical parameters such as initial pH, initial Cd and Pb concentration, adsorbent dosage, and contact time were tested. SEM/EDX images confirmed the adsorption of Pb and Cd with surface physical and chemical changes. The maximum Pb removal was noted at pH 6 using NB (96%) and at pH 8 for RH (90%), and the maximum Cd removal by NB was recorded at 8 pH (91%) and by RH at pH 6 (87%). The decline in adsorption intensity at lower pH suggested protonation of the adsorbent surface causing cation-cation repulsion. Most of the adsorption occurred within the initial 60 min. A continuous gradual increase in the adsorption with time suggested multilayer formation. Of the three isotherms, the Freundlich model fits the present data best, implying an infinite surface coverage and indicating the potential for multilayer adsorption of Pb and Cd on the surfaces of RH and NB adsorbents. In conclusion, this study highlights the promising potential of NB as a cost-effective adsorbent for the removal of Cd and Pb ions from aqueous solutions.

UV-modified biochar-Bacillus subtilis composite: An effective method for enhancing Cd(II) adsorption from water

The adsorption of Cd(Ⅱ) in sewage by single-modified biochar systems have limitations, whereas composite modification can enhance the efficiency. In this study, reed straw biochar and Bacillus subtilis were used as raw materials. UV radiation was employed to modify the biochar, and subsequently, Bacillus subtilis was loaded onto the biochar by adsorption, creating modified biochar composites. The Cd(II) adsorption performance and removal efficiency of these composites were then investigated. It was characterized by BET, SEM-EDS, FT-IR, XRD and ZETA potential analysis. Adsorption experiments were conducted under varying conditions (initial Cd(Ⅱ) concentration, UV radiation time, initial pH, etc.), with adsorption isotherms and kinetic models used. Results indicated that 24 hours UV radiation significantly enhanced adsorption performance, increasing the biochar’s surface area by 40 % and pore volume by 20 %, and introducing numerous pores and oxygen-containing functional groups to the biochar's surface. Significantly enhancing the saturation adsorption capacity for Cd(II) from 23.98 mg/g to 49.93 mg/g after UV- Modified biochar was loaded with Bacillus. Modified biochar composites performed better compared to single-modified biochar across different initial Cd(Ⅱ) concentrations, particularly in slightly alkaline environments. The primary adsorption mechanisms were chemical adsorption, such as ion exchange and surface precipitation. The synergistic effect of UV radiation and microbial loading significantly enhanced Cd(Ⅱ) adsorption efficiency. This study demonstrates that composite modification is a more efficient method, aiding in the removal of heavy metal ion Cd(Ⅱ) from water.

Dihydrotetrazine-Functionalized Zirconium-Based Metal-Organic Frameworks for High-Capacity Oil Denitrogenation.

High structural stability, dual organic-inorganic nature, and tunability in chemical functionality are promising characteristics of zirconium-based metal-organic frameworks (Zr-MOFs). These properties assist Zr-MOFs in extending their applications in various fields, especially adsorptive removal of pollutants. In this work, two well-known Zr-MOFs (UiO-66(Zr) and MIL-140(Zr) with the formula Zr6O4(OH)4(BDC)6, H2BDC is benzene 1,4-dicarboxylic acid) were synthesized and decorated with a dihydrotetrazine functional group through postsynthesis linker exchange (PSLE). Two dihydrotetrazine (DHTZ)-functionalized frameworks, UiO-66(Zr)-DHTZ and MIL-140(Zr)-DHTZ, were applied for the removal of quinoline (Qui) and indole (Ind) from the model oil. The results of adsorption experiments at room temperature display that these functionalized Zr-MOFs have significantly improved removal capacities for Qui (875% for UiO-66(Zr)-DHTZ and 303% for MIL-140(Zr)-DHTZ) and Ind (722% for UiO-66(Zr)-DHTZ and 257% for MIL-140(Zr)-DHTZ). Mechanistic studies based on X-ray photoelectron (XPS) and Fourier-transform infrared (FT-IR) spectroscopies reveal that there is a specific kind of host-guest interaction between dihydrotetrazine and nitrogen-containing compounds (NCCs). UiO-66(Zr)-DHTZ adsorbs 1426 mg·g-1 Qui and 1176 mg·g-1 Ind, while MIL-140(Zr)-DHTZ adsorbs 619 mg·g-1 Qui and 511 mg·g-1 Ind. The lower adsorption capacities of MIL-140(Zr)-DHTZ compared to UiO-66(Zr)-DHTZ are related to its lower surface area (783 m2·g-1 versus 330 m2·g-1). The recyclability of the frameworks goes up to five cycles without any significant decrease in the removal capacity. These results indicate that dihydrotetrazine-functionalized Zr-MOFs are highly stable platforms with superior adsorption capacity compared to basic and neutral NCCs.

Adsorption of aqueous insensitive munitions compounds by graphene nanoplatelets

Mitigation strategies for potential environmental impacts of insensitive munition (IM) compounds, including 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), nitroguanidine (NQ), and methylnitroguanidine, (MeNQ) are being considered to enhance sustainability of current or potential IM formulations. Graphene nanoplatelets (GnPs) were investigated for adsorptive removal of each compound. GnPs were characterized to determine surface areas, along with particle size and zeta potential at different pH and ionic strength conditions. Adsorption kinetics and isotherm studies were conducted, comparing results against granular activated carbon (GAC). Ionic strength, pH, and temperature were adjusted to inform impacts on adsorptive behaviors and performance. The results indicated that GnPs adsorbed IM compounds more rapidly than GAC. Additionally, GnPs removed DNAN with greater capacity compared to GAC, likely due to π-π interactions. GnPs removed other compounds via van der Waals forces, while GAC exhibited greater adsorption capacities due to higher surface area. Although negative charges associated with GnPs and dissociated NTO species hindered adsorption, pH and ionic strength did not impact other compounds. Moreover, this study reports the first environmental treatment technique for MeNQ. Overall, these findings suggest that GnPs are a promising treatment technology for IM-laden waters, particularly those with compounds like DNAN where specific interactions enhance removal efficiency.

Adsorptive removal of Fe and Cd from the textile wastewater using ternary bio-adsorbent: adsorption, desorption, adsorption isotherms and kinetic studies

Ternary bio-adsorbent was synthesized by using sisal fiber as a base with the integration of conductive polymer; polyaniline (PANI), supported with zero-valent iron nanoparticles by chemical activation with potassium hydroxide. The activation temperature impact on adsorption properties of Sisal fiber composite activated carbon was studied. The activation temperatures had a major effect on adsorption process as 100% removal efficiency was attained at 800 °C activated temperature. Scanning electron microscopy (SEM) was used for surface analysis of the adsorbent. Adsorption isotherms (Langmuir, Freundlich and Temkin) were examined and the negative values of 1/nF\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1/n_{F}$$\\end{document} demonstrated that the adsorption data does not match with Freundlich model for chemisorption. The pseudo second order and Elovich kinetics correlation coefficients for the retention of Fe and Cd to solid-phase interface at SF-800/NP/PANI (C) offered a better correlation for the bio-adsorption of Fe and Cd than pseudo first order kinetic. However, the pseudo second order kinetic attained a surpassing interaction for the bio-adsorption of Fe (0.989) than Cd (0.966); while the Elovich kinetic attained a surpassing interaction for the bio-adsorption of Cd (0.975) than Fe (0.945). The recovery and recycling stability of the bio-adsorbent composites were studied.

Development an effective adsorptive treatment strategy for the removal of cadmium from textile wastewater by CuBi2O4@Fe3O4 nanocomposites

In this study, copper-bismuth oxide/iron oxide (CuBi2O4@Fe3O4) nanocomposites were prepared by microwave-assisted synthesis and used as adsorbents for the adsorptive removal of cadmium from textile wastewater. The pH/volume of buffer solution, mixing type/period and adsorbent dosage were optimized univariately to enhance the removal efficiency of the adsorbent and determined as 1.5 mL of pH 8.0 buffer solution, vortexing for 60s, and 30 mg of CuBi2O4@Fe3O4 nanocomposite material. Following the determination of the optimum parameters, equilibrium adsorption studies were performed at five different initial concentrations of cadmium within the range of 0.50 − 10 mg L−1 in textile wastewater. A matrix-matching calibration strategy was utilized for the accurate and precise quantification of cadmium in the wastewater matrix with a R 2 value of 0.9961. The percent removal efficiencies were calculated within the range of 77.2 − 81.5% for the adsorptive removal of cadmium ions from textile wastewater in the equilibrium adsorption experiments. Furthermore, the Langmuir, Freundlich, and Sips adsorption isotherm models were employed for modeling the equilibrium data, and the results showed that all the models fitted well with the experimental data with R2 values higher than 0.99. The simple and efficient batch adsorption process developed was successfully utilized to remove cadmium ions from textile wastewater.

Biosynthesis of lead oxide nanoparticles using mulberry leaf extract for adsorptive removal of diazine black dye

Biosynthesis of lead oxide nanoparticles using mulberry leaf extract for adsorptive removal of diazine black dye