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Dyeing industries release their hazardous dyeing effluents into the environment which affects the human health and ecosystem. Hence, the removal of dye from waste‐water is mandatory one. In this present study, focus on the fabrication of bio‐clay‐ceramic hybrid composites by dispersing bentonite (BT) clay and ceramic hydroxyapatite (HA) into alginate (Alg) and gelatin (Gel) polymeric matrixes by in‐situ method which gives BTHAAlg and BTHAGel hybrid composites for methylene blue (MB) removal. The various adsorption influencing parameters such as shaking time, adsorbent dosage, pH and initial MB concentration were optimized under batch method. The highest MB adsorption capacities of BTHAAlg and BTHAGel composites were found to be 43.70 and 47.50 mg/g respectively with optimized conditions of 100 mg/L of initial MB concentration, 40 min shaking time and 0.1 g dosages. In pH studies, the high MB adsorption capacity of bio‐clay‐ceramic composites were noticed at pH 11. The characterization techniques like FTIR, SEM and EDAX analysis were performed to find the physico‐chemical properties of bio‐clay‐ceramic composites. The equilibrium data of hybrid composites towards MB adsorption was well fitted with Langmuir isotherm model than D‐R and Fruendlich models because of higher r and low sd values. The negative values of ▵Go at three different temperatures (303, 313 and 323 K) indicate that the spontaneous nature of MB adsorption, while positive values of ΔHo and ΔSo revealed that the MB adsorption onto hybrid composites was endothermic in nature and more randomness occurred at solid/liquid interfaces. In kinetic studies, the MB adsorption onto hybrid composites was well fitted with pseudo‐second‐order and intra‐particle diffusion models. The electrostatic attraction and hydrogen bonding plays a dominant role in MB adsorption onto BTHAAlg and BTHAGel bio‐clay‐ceramic composites. The regeneration studies proposed that the hybrid composites can be reusable upto five cycles. Hence, the developed bio‐clay‐ceramic hybrid composites were act as best adsorbents for MB removal. [ABSTRACT FROM AUTHOR]

In the present study, we have fabricated magnetic nanocomposite based on the starch and salicylaldehyde resin embedded with magnetic Fe 3 O 4 nanoparticles (SS@Fe 3 O 4). The fabricated nanocomposite was characterized using various analytical methods including XRD, SEM, FTIR, TGA, TEM, BET and XPS. As-fabricated nanocomposite was used for the adsorption of Pb(II) and Cd(II) from aqueous solution. The adsorption results revealed that the maximum adsorption capacity was found to be 265.4 and 247.2 mg/g for Pb(II) and Cd(II) respectively at pH 6 and room temperature. The adsorption kinetic results support that the adsorption of both the toxic metals was carried out via second order reaction and the rate constants were found to be 6.31 × 10−5 and 7.18 × 10−5 g·mg−1·min−1 for Pb(II) and Cd(II) respectively. The adsorption isotherm displays the Langmuir adsorption isotherm and supports the monolayer and mainly chemisorption with poor physisorption. Additionally, the thermodynamic parameters were evaluated and the adsorption came true in exothermically and spontaneously with both Pb(II) and Cd(II). As-fabricated starch based magnetic nanocomposite displays excellent adsorption as well as outstanding reusability. Therefore, these outcomes support that the SS@Fe 3 O 4 nanocomposite can be used as a promising adsorbent for industrial application. Unlabelled Image • Starch based magnetic nanocomposite was fabricated with salicylaldehyde. • As-fabricated nanocomposite was used for the adsorption of Pb(II) and Cd(II) from aqueous solution. • The effects of pH value, contact time and concentration on the adsorption process were investigated. • Pb(II) and Cd(II) adsorption followed the pseudo-second order kinetics and Langmuir isotherm model. [ABSTRACT FROM AUTHOR]

In the present study, the magnetic nanocomposite is fabricated using chitosan, thiobarbituric acid, malondialdehyde and Fe 3 O 4 nanoparticles (CTM@Fe 3 O 4). The fabricated nanocomposite (CTM@Fe 3 O 4) is characterized using FTIR, TGA, BET, XRD, Raman, XPS, FESEM, and HRTEM techniques. The results of BET analysis confirmed that the nanocomposite has a mesoporous structure with high surface area of 376 m2 g−1 and high pore volume 0.3828 cm3 g−1. The adsorption of tetracycline (TC) onto CTM@Fe 3 O 4 adsorbent is carried out using batch technique by changing several factors such as pH, concentration, contact time, and temperature. Langmuir and pseudo-second-order nonlinear models were found to be the best-fit models to predict isotherms and kinetics of adsorption, respectively. The highest adsorption capacity of 215.31 mg/g was achieved at the optimum conditions of 0.05 g adsorbent dosage, 60 mg/ L TC concentration. Overall, results demonstrated that CTM@Fe 3 O 4 nanocomposite was an excellent adsorbent material with superparamagnetic properties, which allowed the separation as well as recovery of the adsorbent from aqueous solution using external magnet for effective industrial applications. Unlabelled Image • Mesoporous nanocomposite of chitosan/thiobarbituric acid/malondialdehyde-Fe 3 O 4 has been prepared. • CTM@Fe 3 O 4 nanocomposites show super-paramagnetic features. • The fabricated nanocomposites show high surface area of 376 m2 g−1 and high pore volume 0.3828 cm3 g−1. • The adsorption kinetics and isotherms can be well-defined by pseudo-second-order model and Langmuir isotherm model. [ABSTRACT FROM AUTHOR]

Adsorption is a commonly used technique for the removal of pollutants from wastewaters. In this study, a magnetic adsorbent (Fe 3 O 4 @BFR) was prepared using biuret-formaldehyde pre polymeric resin (BFR) and Fe 3 O 4 nanoparticles. The adsorption ability of Fe 3 O 4 @BFR was investigated using Cd(II) metal ion as a typical pollutant. Adsorption of Cd(II) was studied as a function of temperature (25–45 °C), pH (2–7), time (5–300 min) and initial Cd(II) concentration (25–75 mg L−1). The morphology, structure and magnetic character of Fe 3 O 4 @BFR nanocomposite were explored using X-ray powder diffraction, Fourier transform infrared spectroscopy, N 2 adsorption-desorption isotherm, scanning electron microscopy and VSM analyses. Adsorption kinetics, isotherms and thermodynamics studies were also carried out. The experimental adsorption data followed the pseudo-first-order kinetic model and Langmuir isotherm with a maximum adsorption capacity of 92.6 mg g−1. The reusability of Fe 3 O 4 @BFR was tested and still over 70% Cd(II) was removed after three cycles. In conclusion, Fe 3 O 4 @BFR nanocomposite showed enormous potential for remediating industrial wastewater polluted by toxic Cd(II) metal ion. • Fe 3 O 4 @BFR was prepared using biuret-formaldehyde pre polymeric resin and Fe 3 O 4 nanoparticles. • Fe 3 O 4 @BFR was used for the adsorptive removal of Cd(II) from aqueous medium. • The process obeys Langmuir isotherm and pseudo first order kinetic model. • The adsorption was increased with increasing the temperature. [ABSTRACT FROM AUTHOR]

In this study, highly porous N/S doped magnetic carbon aerogel (N/S-MCA) was successfully fabricated using sugarcane bagasse based cellulose and used for the removal of bisphenol‑A (BPA) from aqueous solution. The fabricated N/S-MCA nanocomposite derived from cellulose was characterized by various analytical techniques and supports the formation of the N/S-MCA in good yield and high purity. The batch adsorption studies were used for the adsorption of BPA onto N/S-MCA. The maximum removal of the BPA (98–99%) by the N/S-MCA was noted at pH 7, temperature 343 K, and initial BPA concentration of 100 ppm. The adsorption process followed pseudo-second-order reaction kinetics, as well as Langmuir isotherms. The thermodynamic parameters of the adsorption (the Gibbs free energy, entropy, and enthalpy) supported the spontaneity of the adsorption process. The results revealed that the mechanism on the synergistic adsorption between N/S doped magnetic carbon aerogel and BPA will therefore be an important guideline to design a carbon based adsorbent for high-efficient adsorption of environmental pollutants. Unlabelled Image • N/S doped magnetic carbon aerogel (N/S-MCA) was fabricated using sugarcane bagasse. • The (N/S-MCA) nanocomposite showed the high rates of adsorption for BPA. • The adsorption was support the second order adsorption for BPA. • The (N/S-MCA) was regenerated by simply washing with M methanol solution. [ABSTRACT FROM AUTHOR]

Oil spills present the enormous harm to the environment, and its potential remediation for environmental protection is import worldwide. Herein, we report an effective strategy inspired by the lignin based bio-waste date palm pits powder (Phoenix dactylifera L.), which was modified with magnetic Fe 3 O 4 nanocrystals and used as a porous, hierarchical graphite carbon oil/solvent sorption magnetic materials. The fabricated nanocomposite (Fe 3 O 4 @MPC) was characterized using several analytical techniques. The results revealed that Fe 3 O 4 nanoparticles with a 22 nm in average size were embedded into the graphite carbon matrix. The rate of sorption, sorption capacity, oil retention, water uptake, adsorption isotherm model, and kinetic behavior were evaluate and >85% of both oils were adsorbed, onto Fe 3 O 4 @MPC surface in the first 30 min followed by equilibrium in both type of aqueous solution. The batch equilibrium data supported the Langmuir isotherm model with the adsorption capacity about to 23.01 mg/g. The kinetics data was well fitted with pseudo-second-order kinetic model. After saturation, the Fe 3 O 4 @MPC was recycled using ethanol and reused for further cycle. The fabricated nanocomposite exhibited a significant dual oleophilic and hydrophobic nature that can be applicable for oil removal from oil-contaminated wastewaters. Meanwhile, the magnetic properties allowed Fe 3 O 4 @MPC to be separated conveniently and effectively from the solution and used as oil absorbent without touching the oil. Unlabelled Image • Fabrication of highly porous, hierarchical graphite carbon (Fe 3 O 4 @MPC) from date palm pits • Fe 3 O 4 @MPC was used for removal and recovery of diesel and gasoline from aqueous medium. • Fe 3 O 4 @MPC was recycled and used for ten times without any considerable loss in adsorption capacity. • The magnetization saturation value of Fe 3 O 4 @MPC was found to be 37.81 emu g−1. [ABSTRACT FROM AUTHOR]

Abstract Amino functionalized multi-walled carbon nanotubes (NH 2 -MWCNTs) were prepared via chemical modification of the surface of multiwall carbon nanotubes. The magnetic nanoparticles (Fe 3 O 4) were embedded with NH 2 -MWCNTs and the developed magnetic carbon nanotube (NH 2 -MWCNTs@Fe 3 O 4) were characterized via several analytical techniques including FT-IR, Raman, XRD, TEM, SAED, SEM, BET and VSM. The fabricated NH 2 -MWCNTs@Fe 3 O 4 was used for the removal of toxic methylene blue dye (MB) from aqueous medium. The results of VSM indicated that the fabricated NH 2 -MWCNTs@Fe 3 O 4 had magnetic nature and the saturated magnetization was 37.91 emu/g. The effect of initial solution pH, temperature and contact time on MB adsorption was also investigated. The results of adsorption kinetics exhibited that the adsorption followed the linear pseudo-second-kinetic model well. Langmuir and Freundlich isotherm models were applied to understand the adsorption behaviors. The maximum adsorption capacity from the Langmuir isotherm equation reached 178.5 mg g−1 indicated that it was a good adsorbent for MB removal. The thermodynamics parameters such as Gibbs free energy (Δ G 0), enthalpy (Δ H 0) and entropy (Δ S 0), supported the spontaneous and exothermic nature of adsorption. It was noted that after six repetitive cycles, the adsorption capacity of NH 2 -MWCNTs@Fe 3 O 4 was 80% of the original value. Hence, it can be concluded that NH 2 -MWCNTs@Fe 3 O 4 had substantial reusability which made it an economical adsorbent for MB removal from aqueous medium. Highlights • Amino-functionalized magnetic multi-walled carbon nanotubes were prepared. • NH 2 -MWCNTs@Fe 3 O 4 was used as adsorbent for MB dye removal. • Adsorption kinetics and equilibrium isotherm models for MB dye were reviewed. • NH 2 -MWCNTs@Fe 3 O 4 was used for six cycles without significant loss in adsorptive performance. [ABSTRACT FROM AUTHOR]

Herein, trisodium citrate based magnetite nanocomposite (Fe3O4-TSC) was used for malachite green (MG) dye expulsion from aqueous medium. The adsorption tests were executed at different parameters. The maximum adsorption were took place at pH 4 in 40 min. The equilibrium studies were demonstrated using Langmuir and Freundlich isotherms and better agreement was attained with the Langmuir model. The maximum adsorption capacity (qe) was calculated 435 mg g-1 using Langmuir equation. The kinetic parameters displayed that MG adsorption onto Fe3O4-TSC followed pseudo-second-order kinetic model. Furthermore, the thermodynamic analysis suggested the adsorption of MG onto Fe3O4-TSC was impulsive and exothermic. The desorption studies showed the best recovery of MG dye in 0.1 M HCl. Finally, it was found that Fe3O4-TSC can be effortlessly separated from mixed solutions using external magnetic field. [ABSTRACT FROM AUTHOR]

The heavy metal ions pollution is serious threat for aquatic and terrestrial living beings. The adsorption is facile process to encounter the heavy metal pollution. Various types of adsorbents have been developed and used for environmental remediation. The activated carbon is one of the cheapest adsorbent derived from various biomass sources and coupled with diverse materials to fabricate superior adsorbents. In the present work, datestone activated carbon-based zirconium oxide (DSAC/ZrO 2) composite was fabricated and characterized by XRD, SEM, BET and SEM. The surface area, pore volume and average pore diameter of DSAC/ZrO 2 were 153.4 m2 g−1, 0.04 cm3 g−1 and 8.8 nm, respectively. Using batch experiments, sorption of cadmium ions was explored onto DSAC/ZrO 2 composite. To have detail insight into sorption process; the isotherm, kinetics and thermodynamic studies were also performed. The experimental equilibrium data for cadmium adsorption using DSAC/ZrO 2 composite was well fitted to the Langmuir isotherm model and showed the q m 166.7 mg/g at 25 °C. The negative and positive values of ΔG° and ΔH° indicated that the adsorption was spontaneous and endothermic, respectively. Unlabelled Image • Datestone activated carbon zirconium oxide (DSAC/ZrO 2) composite was prepared by facile method. • Adsorption of cadmium ions was investigated onto DSAC/ZrO 2. • Langmuir isotherm fits well to cadmium ions adsorption onto DSAC/ZrO 2. • The maximum adsorption capacity was found to be 166.7 mg/g at 25 °C. [ABSTRACT FROM AUTHOR]

• Fe 3 O 4 @TATS@ATA was prepared and applied for the adsorptive removal of Pb(II) metal. • The maximum adsorption capacity for Pb(II) was 205.2 mg/g at pH 5.7 and 298 K. • Thermodynamic confirmed the spontaneous and exothermic adsorption. • The nanocomposite adsorbent was ease of separate and reusability. Herein, a novel nanocomposite (Fe 3 O 4 @TATS@ATA) was prepared and used for adsorptive removal of Pb(II) ions from aqueous environment. The magnetic nanocomposite (Fe 3 O 4 @TATS@ATA) was characterized using FTIR, TEM, SEM, EDX, element mapping analysis (EMA), TGA analysis, XRD patterns, VSM, BET analysis, XPS spectrum, and zeta potential. The FTIR study confirmed the modification of Fe 3 O 4 nanoparticles with triaminetriethoxysilane and 2-aminoterephthalic acid while XPS analysis (with peaks at 283.6, 285.1, 286.3, 284.5.0, 288.4 eV) displayed the presence of C Si, C N, O C NH, C C/C C and O C O functional groups, respectively on Fe 3 O 4 @TATS@ATA. The BET surface area, average pore size, pore volume and magnetization saturation for Fe 3 O 4 @TATS@ATA were found to be 114 m2/g, 6.4 nm, 0.054 cm−3/g, and 22 emu/g, respectively. The adsorption isotherm data showed that Pb(II) adsorption onto Fe 3 O 4 @TATS@ATA fitted to Langmuir and Dubinin–Raduskevich isotherm model due to better R2 value which was greater than 0.9 and q m of Pb(II) was 205.2 mg/g at pH 5.7 in 150 min. Adsorption kinetics data displayed that Pb(II) adsorption onto Fe 3 O 4 @TATS@ATA was fitted to the pseudo-second-order and Elovich kinetic models. Thermodynamic outcomes exhibited the exothermic and spontaneous nature of adsorption. Results showed that Fe 3 O 4 @TATS@ATA nanocomposite was promising material for efficient removal of toxic Pb(II) from aqueous environment. [ABSTRACT FROM AUTHOR]

In this study, para-aminobenzoic acid functionalized activated carbon (PABA@AC) was successfully synthesized and applied as an adsorbent for removal of malachite green dye (MG) from aqueous system. For characterization of the prepared PABA@AC composite, (FT-IR), (SEM) and (EDX) were used. Impact of many parameters such as pH, amount of PABA@AC composite (m), contact time (t), temperature (T), initial MG concentrations (C o) upon MG adsorption using PABA@AC was investigated to estimate the optimum parameter conditions for adsorption. The results showed that the optimized parameter values of pH solution, contact time, adsorbent dose, and temperature were 7, 240 min, 30 mg and 25 °C, correspondingly. The isotherm adsorption and kinetic studies showed that the adsorption process was well fitted to Langmuir isotherm and Pseudo-first-order kinetic models, respectively. The maximum MG adsorption capacity was 66.87 mg/g by Langmuir model. The thermodynamic studies showed that the adsorption process was exothermic and spontaneous. Unlabelled Image • The coating of AC surface with Para-aminobenzoic acid allowed to obtain a composite. • PPABA@AC composite showed high adsorption capacity for MG dye. • Maximum MG adsorption capacity was 66.87 mg/g by Langmuir model. [ABSTRACT FROM AUTHOR]

In the present work, we have successfully developed 2-amino-5-guanidinopentanoic acid modified activated carbon (AGDPA@AC) for the effective removal of methylene blue (MB) dye from aqueous medium. The AGDPA@AC was characterized using different instrumental techniques viz., SEM, EDX, FTIR, TGA and zeta potential. The influence of different parameters viz. pH, initial MB concentration, contact time and temperature on the adsorption capacity was investigated. The maximum adsorption capacity of MB of on AGDPA@AC was found at pH 8 and 120 min. The maximum Langmuir adsorption capacity of AGDPA@AC was 219.9 mg/g at 25 °C. The adsorption followed Langmuir isotherm and pseudo-second order kinetic models well. The result of thermodynamic data showed that the adsorption was spontaneous and exothermic in nature. The binding of MB dye onto AGDPA@AC surface was through electrostatic interactions. Regeneration studies indicated that the adsorbent could successfully retain MB, even after four cycles. The adsorption percent of AGDPA@AC for MB dye was 75% even after four adsorption-desorption cycles. Unlabelled Image • Arginine based composite (AGDPA@AC) was synthesized. • MB dye was efficiently removed using AGDPA@AC. • AGDPA@AC exhibited high adsorption capacity for MB dye. • The mechanism of adsorption was electrostatic interaction and π-π interaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • MCGHCOF beads were prepared and used for fluoride adsorption studies. • MCGHCOF beads remove fluoride both in standard and field water. • MCGHCOF beads are regenerable and regenerated upto six cycles. • MCGHCOF beads are providing water with safe fluoride levels. The developed biocompatible materials like covalent organic frameworks (COFs) and hydroxyapatite acquire significant defluoridation capacity (DC). But because of their powder nature, creates column blockage, pressure drop during field investigations and difficult in separation after fluoride adsorption. To address these problems, COFs and hydroxyapatite were fabricated in the usable form of beads using chitosan, gelatin and iron oxide materials as magnetic chitosan–gelatin/hydroxyapatite/covalent organic frameworks (MCGHCOF) bio-beads were developed and it was potentially applied for the removal of fluoride from water. The MCGHCOF bio-beads surface and their properties were described with FTIR, EDAX, SEM and XRD analysis. The adsorption studies were performed under the batch method. The HCO 3 – ion has a vital inhibitory effect on DC and this may be because of the similar ionic size of fluoride and HCO 3 –. The enhanced DC of MCGHCOF beads was found to be 4992 mgF-.kg−1 in 30 min at pH 7. Isotherm experimental data of fluoride adsorption was apt with Langmuir isotherm than Fruendlich and D-R isotherm models. The defluoridation system is endothermic and its spontaneous nature was demonstrated with thermodynamic studies. Kinetic studies of experimental data of fluoride adsorption were well-fitted with pseudo-second-order and intraparticle diffusion. The complexation and electrostatic interaction play a predominant role in fluoride adsorption by MCGHCOF beads. The MCGHCOF bio-beads are stable and are reusable upto six cycles. The collected field water sample was examined using MCGHCOF beads and it reduced the fluoride concentration to the tolerable drinking water threshold as recommended by WHO (1.5 mg L−1). [ABSTRACT FROM AUTHOR]

In this study, mesoporous carbonated TiO 2 nanoparticles were synthesized by sol-gel route using a complex [Ti(OH 2) 6 ]3+·3Cl− and a modifying agent Na 2 CO 3 and used as an adsorbents for Sr(II) removal from aqueous medium. The characterization of nanoadsorbents was accomplished using XRD, SEM, EDS, TEM, TG-DTG-DTA, IR, BET, pH PZC analyses. It was found that the sizes of carbonated TiO 2 nanoparticles was ~4 nm. The presence of mononuclear bidentate carbonate groups on the titania surface was approved by IR spectroscopy. The kinetic data was analyzed by pseudo-first-order, pseudo-second-order, Elovich, and an intraparticle diffusion models. The adsorption isotherms were fitted by using Langmuir, Freundlich, and Dubinin–Radushkevich models. The fittings show that the pseudo-second-order kinetics and Langmuir isotherm are suitable models for the adsorption process. The sample with 4% (wt.) of carbonate groups showed the best adsorption performance towards Sr(II) cations. The mesoporous carbonated samples demonstrated a higher adsorption capacity for strontium ions than the basic TiO 2. The adsorption capacities of modified 2C-TiO 2 , 4C-TiO 2 and 8C-TiO 2 samples were 170.4, 204.4, 190.8 mg/g respectively, while it was 70.9 mg/g for the unmodified TiO 2 towards Sr(II). Higher removal of Sr(II) was observed in the alkaline medium due to the formation of SrОН+ cations. A mechanism for Sr(II) adsorption was described and the number of chemosorbed ≡Ті(О 2 СО) groups and active adsorption centers onto unmodified and modified TiO 2 surface were calculated. The titania adsorbents have high reusability and retain their adsorption capacity during five adsorption-desorption cycles. The presented results indicated that the mesoporous carbonated adsorbents were appropriate materials for the removal of Sr(II) from aqueous medium. Unlabelled Image • A new mesoporous TiO 2 with chemosorbed carbonate groups has been synthesized. • Sr(II) successfully removed using a carbonated mesoporous titania • Sr(II) removal capacity of the 4C-TiO 2 is 204.4 mg/g at natural pH • Titanocarbonate groups provide the formation of surface acidic centers. [ABSTRACT FROM AUTHOR]

• The adsorption analysis of heavy metals was carried out using GO/CuO-NPs. • Characterization showed uniform distributions of GO over CuO-NPs. • Maximum Ni2+ and Cd2+ removal of 99.16 and 98.84 % were observed at 15 min time. • The optimum results were observed at flow rate of 4 mL/min and a bed height of 1 cm. • Pseudo-second order model and Langmuir isotherms were best fitted with data. During the past few decades, water contamination has raised a huge concern due to rapid industrialization, agricultural wastes, metal galvanizations, and leather industries as a result of the discharge of organic pollutants, dyes and heavy metals. The present study investigates the synthesis of copper oxide nanoparticles (CuO-NPs) and graphene oxide-copper oxide nanoparticles (GO/CuO-NPs) for heavy metal ions adsorption like Ni2+ and Cd2+ from wastewater. For this purpose, batch and continuous adsorption studies were performed. The chemical and physical characteristics were analyzed by FTIR, XRD, SEM, and AFM. AFM analysis confirmed the hexagonal structure and an average diameter of 79.91, 82.01 and 21.45 nm for GO/CuO-NP, CuO n , and CuO m , respectively. In batch scale, it is concluded that GO/CuO-NPs showed the best adsorption capacity for Ni2+ and Cd2+ than CuO n and CuO m at pH value of 8, adsorbent dose of 250 mg, initial concentration of 50 mg/L, a contact time of 15 min. GO/CuO-NP showed the maximum Ni2+ and Cd2+ removal of 99.16 and 98.84 % respectively at 15 min contact time. Similarly, the maximum Ni2+ and Cd2+ ions removal of about 99.37 and 99.18 % was observed with GO/CuO-NPs at an adsorbent dose of 250 mg and 50 mg/L dye concentration. The adsorbent isotherm and kinetic analysis revealed that the results were best fitted with Langmuir isotherms and the Pseudo-second order model, respectively. While in continuous adsorption analysis, GO/CuO-NPs showed the best adsorption capacity for Ni2+ and Cd2+ than CuO n and CuO m at an initial concentration of 50 to 75 mg/L, a flow rate of 4 mL/min, and a bed height of 1.5 to 2 cm. However, the present study provides valuable insight into novel nanocomposites' development to eliminate Ni2+ and Cd2+ from industrial wastewater. [ABSTRACT FROM AUTHOR]

Fabrication of novel adsorbent with high surface area and high adsorption capacity is in urgent demand for water treatment, Therefore, in this study, a nanocomposite include Schiff base polymer and magnetic Fe 3 O 4 nanoparticles was synthesized and characterized using analytical techniques including FTIR, TGA, XRD, Raman, SEM, TEM, XPS and N 2 adsorption-desorption studies. The fabricated magnetic porous organic polymer (MPOP) was used as an efficient adsorbent for the removal of Cd(II) and Hg(II) from aqueous solution. The adsorption kinetic results revealed that both metal ions; Cd(II) and Hg(II) supported the pseudo-second-order adsorption kinetic model. The Langmuir isotherm model supported the adsorption over MPOP with a maximum adsorption capacity of 308.9 mg g−1 and 284.6 mg g−1 for Cd(II) and Hg(II), respectively. The thermodynamic results indicated that the adsorption of both metal ions was spontaneous and endothermic. The regeneration results suggested that the novel MPOP was a promising reusable adsorbent for the adsorption of heavy metal ions from aqueous solution. • Synthesis of magnetic porous organic polymer (MPOP) using Schiff base • The MPOP nanocomposite showed the high rates of adsorption for Cd(II) and Hg(II). • The adsorption was followed pseudo second order kinetics for both Cd(II) and Hg(II). • The MPOPC was regenerated by simply washing with 0.1 M HCl solution. [ABSTRACT FROM AUTHOR]

In this study, a magnetic composite was synthesized using chitosan, diphenylurea and formaldehyde with magnetic nanoparticles, (MnFe 2 O 4) via condensation polymerization. The newly synthesized magnetic nanocomposite (CDF@MF) was characterized using several analytical techniques including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) and etc. To investigate the applicability of CDF@MF, it was employed as an adsorbent for rapidly removal of an antibiotic, namely, tetracycline (TC), from aqueous solution using several factors such as pH, the adsorbent dose, the initial concentration and the contact time. The adsorption kinetics results exhibited that the adsorption process followed a pseudo-first-order model. The maximum adsorption capacity for TC was calculated to be 168.24 mg/g based on the Langmuir adsorption isotherm model, with fitting correlation coefficient (R 2), 0.9955.The regeneration study advice that no major change in the adsorption capacity was noticed and show 157.97% adsorption performance after seven cycles. These results are standing to indicate that the prepared porous CDF@MF could be used as a low-cost, effective, reusable adsorbent for pharmaceutical wastewater treatment. Unlabelled Image • Magnetic polymer nanocomposite was fabricated using chitosan, diphenyl urea and formaldehyde. • The CDF@MF nanocomposite showed the high rates of adsorption for TC. • The adsorption was support the firs order adsorption for TC. • The adsorbent was regenerated by simply washing with 0.1 M methanol solution. [ABSTRACT FROM AUTHOR]

Due to increasing antibiotic pollution in the water environment, green and efficient adsorbents are urgently needed to solve this problem. Here we prepare magnetic bamboo-based activated carbon (MDBAC) through delignification and carbonization using ZnCl 2 as activator, resulting in production of an activated carbon with large specific surface area (1388.83 m2 g−1). The influencing factors, such as solution pH, initial sulfadiazine (SD) concentration, temperature, and contact time, were assessed in batch adsorption experiments. The Langmuir isotherm model demonstrated that MDBAC adsorption capacity on SD was 645.08 mg g−1 at its maximum, being higher than majority of previously reported adsorbents. In SD adsorption, the kinetic adsorption process closely followed the pseudo-second kinetic model, and the thermodynamic adsorption process was discovered to be exothermic and spontaneous in nature. The MDBAC exhibited excellent physicochemical stability, facile magnetic recovery and acceptable recyclability properties. Moreover, the synergistic interactions between MDBAC and SD mainly involved electrostatic forces, hydrogen bonding, π-π stacking, and chelation. Within the benefits of low cost, ease of production and excellent adsorption performance, the MDBAC biosorbent shows promising utilization in removing antibiotic contaminants from wastewater. [Display omitted] • We investigate a novel bamboo-based magnetic activated carbon. • The absorbent has high surface area, well-developed pores and is recyclable. • The maximum adsorption capacity on sulfadiazine is 645.08 mg g−1 • The adsorption of sulfadiazine is based on single-molecule surface chemisorption. • This is a promising novel cost-effective and environmental-friendly absorbent. [ABSTRACT FROM AUTHOR]

In this study, (hemi)cellulosic biochar-based environment-friendly non-toxic nanocomposite (n Ag-AC) was fabricated for an inordinate overlook of toxic dye-laden wastewater depollution. This hybrid nanocomposite grafted with silver nanoparticles, numerous hydroxyl and π-bond containing functional groups exhibited outstanding physicochemical properties. FESEM images indicated the heterogeneous porous structure of n Ag-AC, while BET analysis revealed mesoporous property with a significant increment of overall surface area (132%). Imbedding of silver nanoparticles and the presence of multiple hydroxyl groups was evident from the XRD and XPS spectrum. Further, the TGA result indicated excellent thermal stability, and FTIR analysis suggested the involvement of surface functional groups like –OH, =C = O, =NH, =C = C = , and –CH in Rhodamine B (RhB) adsorption. The adsorbent matrix provided the overall mechanical strength and facilitated recycling, while the functional matrix (biochar) provided the adsorptive locus for augmented RhB adsorption efficiency (92.77%). Experiments pertaining to adsorption isotherms and kinetics modeling suggested that RhB was removed through multilayer chemisorption on the heterogeneous n Ag-AC surface. The main RhB adsorption mechanism included cumulative efforts of H-bindings, π-π stacking interaction, pore-filling, and electrostatic interactions. The n Ag-AC maintained mechanical robustness with significant RhB adsorption even after three consecutive regeneration cycles signifying facile recycling. The n Ag-AC displayed an outstanding efficacy for the real industrial wastewater depollution, indicating high effectiveness for practical environmental applications. Finally, the cost analysis (incorporating economic, environmental, and social dimensions) suggested a significant role of the n Ag-AC in promoting and establishing sustainable development with the circular economy. [Display omitted] • n Ag-AC showed excellent RhB removal efficiency and adsorption capacity of 46.38 mg g−1. • RhB removal involves π-π stacking, pore-filling and electrostatic interaction. • -OH, =C = O, =NH, =C = C = , –CH groups are actively involved in RhB adsorption. • RhB adsorption was multi-layered chemisorption onto heterogeneous n Ag-AC surface. • The nAg-AC promotes environmental sustainability through a circular economic approach. [ABSTRACT FROM AUTHOR]

This study deals with the removal of nitrate from water by electrocoagulation process using zinc and stainless steel as anode and cathode respectively. The optimizations of various experimental operating parameters like effect of electrolyte pH, current density, temperature, and inter-electrode distance on the removal of nitrate were carried out. The effect of co-existing anions such as carbonate, phosphate, silicate and phosphate was studied on the removal efficiency of nitrate. The results showed that the optimum removal efficiency of 69% was achieved. The maximum removal efficiency was achieved at a current density of 0.1 A dm − 2 and pH of 7.0. First and second-order rate equations were applied to study adsorption kinetics and the adsorption process follows second order kinetics model with good correlation. The Langmuir adsorption isotherm favors monolayer coverage of adsorbed molecules for adsorption nitrate. Thermodynamic parameters, including the Gibbs free energy, enthalpy, and entropy, indicated that the adsorption of nitrate on zinc hydroxide was feasible, spontaneous and endothermic. [ABSTRACT FROM AUTHOR]

A novel Schiff base ligand based nano-composite adsorbent (NCA) was prepared for the detection and removal of copper (Cu(II)) ions in wastewater samples. Upon the addition of Cu(II) ions to NCA at optimum conditions, the clear color was visible to the naked-eye in the detection system. This NCA exhibited an obvious color change from yellowish to dark green in the presence of Cu(II) ions in aqueous solution. The limit of detection was found to be 0.16 μg/L by optical detection. The NCA could detect the Cu(II) ions over other foreign ions with high sensitivity and selectivity. For adsorption behavior, influences several factors such as solution pH, contact time, concentration for Cu(II) ion adsorption was investigated by batch experiment in detail. The results showed that neutral solution pH was suitable to get optimum Cu(II) ions adsorption. Also an extending contact time was favorable for improving adsorption efficiency. The adsorption process of Cu(II) ions by the NCA was followed the Langmuir adsorption isotherm model. The maximum adsorption capacity of Cu(II) ions by the NCA from the Langmuir isotherm model was 173.62 mg/g. The mesoporous NCA exhibited higher adsorption capacity compared with some other reported diverse materials. In the multi-component system, the competing ions did not significantly interfere in the adsorption of Cu(II) ions. The adsorbed Cu(II) ions was effectively eluted with 0.25 M HCl and remain the almost same functionality for many cycles use. Even in seven consecutive cycles, the NCA showed great potential in the optical Cu(II) ions removal from wastewater. Then the proposed NCA could be used a promising adsorbent for the clean-up of Cu(II) ions in wastewater treatment. [ABSTRACT FROM AUTHOR]

Polysaccharide-based hydrogels offer a great overlook for environmental applications and help in the elimination of various noxious pollutants from the water system. Novel carrageenan and itaconic acid-based superadsorbent hydrogel having appreciable swelling properties and adsorption capacity towards Methylene blue (MB), Crystal violet (CV), and Methyl Red (MR) was synthesized by suspension polymerization technique. The swelling study showed the dependency upon the temperature in which the swelling rate increased with increasing temperature with a maximum swelling rate of 417% at 318 K. For ascertaining the maximum adsorption capacity, various influential parameters such as contact time, adsorbent dose, dye concentration, and temperature were systematically studied. Maximum adsorption capacity as calculated from the Langmuir isotherm was 2439.02, 1111.11, and 666.68 mg/g for MB, CV, and MR, respectively. Thermodynamic studies revealed the spontaneous nature of the undertaken dye adsorption experiment. Overall, the present study reveals that the synthesized superadsorbent hydrogel can be used as an efficient adsorbent for the removal of dyes from an aqueous solution. [Display omitted] • Superadsorbent hydrogel designed for the adsorptive removal of cationic dyes. • Maximum adsorption capacity obtained for MB followed by CV and MR. • Results have been analyzed by isotherm and kinetic studies. • Superadsorbent hydrogel successfully recycled for consecutive 5 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Trimetallic nanoparticles were incorporated onto SiO 2 matrix. • Facile microwave reduction method was used. • Adsorption of Methylene blue (MB) dye was carried out. • The maximum adsorption capacity for MB dye was 294.11 mg/g. • Reusability study carried out for six consecutive cycles. The removal of toxic dyes from the wastewater is a serious concern. One of the commonly employed dyes in the textile industry is methylene blue (MB). Its presence in water not only reduces the aesthetic value of the water but also affects aquatic life. Considering this, we have worked on the designing of Bi 2 O 3 -SrO-FeO@SiO 2 nanocomposite using a simple microwave irradiation method. The synthesized Bi 2 O 3 -SrO-FeO@SiO 2 nanocomposite was characterized by various techniques such as scanning electron microscope, transmission electron microscope, X-Ray diffractometer, elemental mapping, Energy- dispersive X-Ray, and X-ray photoelectron spectrophotometer. The adsorption technique was utilized for the effective removal of MB using Bi 2 O 3 -SrO-FeO@SiO 2 nanocomposite. Effects of various factors such as the concentration of MB, amount of Bi 2 O 3 -SrO-FeO@SiO 2 nanocomposite, and reaction time were undertaken for getting some optimized parameters for the further experiments. Adsorption isotherm models such as Langmuir, Freundlich, and Temkin were employed for the adsorption data. Besides, adsorption kinetic models such as Pseudo- first order and Pseudo- second-order were also studied for determining the rate of the undertaken adsorption process. At last, the reusability of the Bi 2 O 3 -SrO-FeO@SiO 2 nanocomposite was studied for six consecutive cycles for elaborating the practical application of the synthesized adsorbent. [ABSTRACT FROM AUTHOR]

The water resources contamination in an alarming concern for sustainable environment. This has led to development of new technologies and materials for waste water detoxification. In the present study, we have fabricated novel trimetallic based mixed oxides decorated reduced graphene oxide (rGO) composite using facile microwave method and utilized it as an adsorbent for the removal of congo red dye from aqueous solution. The final composite showed highly agglomerated metal oxides present on the rGO surface. The high surface area and activity of the synthesized adsorbent resulted in its high adsorption capacity of 333.32 mg/g for congo red. The Langmuir model better explained the isotherm data indicating the monolayer adsorption of congo red molecules onto Ag 2 O–Al 2 O 3 –ZrO 2 /rGO surface. The grander adsorption ability of Ag 2 O–Al 2 O 3 –ZrO 2 /rGO towards organic dye indicate its probable utilization in the removal of other dyes also from wastewater. • Trimetallic oxides decorated into rGO matrix were synthesized. • Adsorption of congo red from aqueous solution was investigated. • Maximum adsorption capacity of 333.32 mg/g was obtained using Langmuir isotherm. • Langmuir model better explained the adsorption isotherm data and mechanism. [ABSTRACT FROM AUTHOR]

This review is devoted to the study of the adsorption behavior of uranium(VI) using titanium dioxide based sorbents. Uranium pollution of groundwater, soil and rocks is a big problem due to the long-term toxicity of uranium compounds. Waste uranium is a by-product of the enrichment process used in the production of atomic energy, and the danger associated with this is due to the radioactivity of uranium and its toxicity as a heavy metal. The mechanisms of uranium adsorption by titania adsorbents are presented here, depending on the various environmental conditions, as well as the kinetics of adsorption. The influence of the structural characteristics of the sorbents on the adsorption behavior of uranium is depicted. Surface chemistry and sorption activity of titanium dioxide were reviewed. Examples of new advanced sorbents with nanometer dispersion are described and the parameters of adsorption isotherms are also presented. One of the practical tasks of this analytical review is to obtain information for modeling the behavior of uranium in the water/adsorbent system due to anthropogenic pollution. • The mechanisms of U(VI) adsorption by titania adsorbents are presented. • Surface chemistry and adsorption activity of titanium dioxide were reviewed. • Examples of new advanced titania adsorbents are described. [ABSTRACT FROM AUTHOR]