Super effective recovery of industrial wastewater contaminated by multi-disperse dyes through hydroxyapatite produced from eggshell

The current investigation signified to produce hydroxyapatite (HA) from eggshell via self-combustion route to uptake disperse dyes, Blue 60, Red 152, and Yellow 23, from the industrial single, and multi-contaminated systems. The fabrication process involved subjecting the calcined eggshell powder to nitric acid, and urea solutions followed by heating at 90 °C to form a gel for auto-ignition stage. The self-combustion favors to create the meso-porous HA particles with average diameter of 35 nm, leading to achieve a superior adsorption capacity, 520–950 mg g^?1, for the removal of disperse dyes from the multi-contaminated system. The lowest adsorption capacity, 520 mg g^?1, was determined for the treatment of concentrated wastewater, containing 66.6% blue dye, and the same proportions of red, and yellow dyes, 16.7%. Although the chemical structure of disperse dye could affect the remediation, the adsorption capacity follows the order of blue > red > yellow. The adsorbent performance in the treatment of multi-contaminated systems did not coincide well with the adsorption affinity order. The calcination of fragile powder at 700 °C led to create pronounced hydrogen bonds which are beneficial to treat the mentioned wastewater. The excellent thermal stability of fabricated adsorbent provided a condition for the regeneration of contaminated HA which is a promising strategy to reuse in the recovery process, and prevent the generation of secondary pollution.     

Vegetable residue of fenugreek (Trigonella Foenum-Graecum), waste biomass for removal of Basic Violet 14 from wastewater: Kinetic,equilibrium, and reusability studies

The present work has focused on the utilization of vegetable residue of Fenugreek (VRF), sustainable and novel adsorbent for sequestration of Basic Violet 14 (BV 14) dye. Effect of various batch operating parameters on BV 14 adsorption has been studied in detail and optimum values were reported as pH of 7.2, adsorbent loading of 0.125 g, shaking time of 105 min and temperature of 323 K. VRF was characterized based on various techniques as FTIR, DLS, zeta potential, SEM-EDS, and BET analysis. Kinetic and equilibrium data have been well exemplified by pseudo 1^st order and Freundlich model, respectively. The maximum uptake capacity was reported to be significant as 177.78 mg/g. Mechanism of BV 14 adsorption on VRF was reported to involve steps as pore diffusion and film diffusion based on reported data fitting to Boyd model. Thermodynamic investigation affirmed adsorption as spontaneous, endothermic and physical in nature. Recovery of adsorbed BV 14 from VRF was conducted using ethanol as an elution media and regenerated VRF was applied for fresh BV 14 adsorption in five cycles. Recovery values were reported to be significant as 98.92% for first cycle and 84.41% for fifth cycle. Similarly, uptake capacity values were reported to be significant as 39.34 mg/g for first cycle and 32.47 mg/g for fifth cycle, which has proved the recovery potential and thus the applicability of VRF for subsequent cycles of BV 14 adsorption. Overall, the present work proved VRF as a promising adsorbent for successful remediation of BV 14 dye.     

Synthesis and characterization of MOF-5 incorporated waste-derived siliceous materials for the removal of malachite green dye from aqueous solution

The synthesis of MOF-5 and its modification have been investigated towards malachite green (MG) dye removal. The modified MOF-5 adsorbents have been prepared using waste-derived siliceous materials, i.e., rice husk ash (RHA) and/or coal fly ash (CFA) at different ratio. The MOF-5/RHA&CFA/2:1 has been chosen as the best adsorbent for MG dye removal from the aqueous solutions. The adsorption characteristics of the modified MOF-5 for MG dye removal was studied varying various parameters. The MG adsorption efficiency increases with increasing the shaking rate and contact time, but remained constant after 300 rpm and 4 h, respectively. The maximum adsorption capacity of 39.47 mg/g was obtained at adsorbent amount of 0.3 g, initial dye concentration of 150 mg/L, temperature of 30 °C, shaking rate of 200 rpm, contact time of 2 h, and original solution pH. The optimum temperature, pH, and amount of adsorbent for effective MG dye adsorption were 40 °C, 11.5, and 0.2 g, respectively. XRD analysis indicated the presence of crystalline materials has become reduced when RHA and CFA were being incorporated in MOF-5. FTIR analysis showed significant functional groups in the spectrum for both prepared and spent adsorbents. The SEM micrograph results revealed the rough surface morphology with many pores on the MOF-5/RHA&CFA/2:1 before MG adsorption and became smooth and less porous after MG adsorption. While BET analysis indicated that the surface area does not affect the MG dye adsorption efficiency. This study showed that modified MOF-5 adsorbents were successfully used for the removal of MG dye.     

High removal of crystal violet dye and tetracycline by hydrochloric acid assisted hydrothermal carbonization of sugarcane bagasse prepared at high yield

At a moderate thermal treatment process, hydrothermal carbonization (HTC) was known as an alternate and green way of preparing carbonaceous material known as hydrochar as an adsorbent. The HTC process requires the inclusion of water as a carbonization medium for the hydrolysis reaction to occur. By adding acid to the HTC water, the hydrolysis reaction was catalyzed, which lowered the reaction time and temperature while also increasing the adsorption efficiency. Overreaction, on the other hand, may occur, lowering the yield as well as the number of functional groups accessible for adsorption. Thus, in this study, Response Surface Methodology by Central Composite Design (RSM-CCD) was employed to investigate and optimize the HCL acid-assisted HTC of sugarcane bagasse (SB) process parameters of loading rate, reaction time, reaction temperature, and HCL acid concentration towards three responses: optimized hydrochar (HC_op) yield, crystal violet (CV) dye removal and tetracycline (TC) removal. The HC_op was characterized using FTIR, FESEM, BET + N₂ gas, and TGA analyses, and the results were compared to hydrochar made without the use of acid (HC_dw). In brief, HC_op has more acidic oxygenated functional groups, stronger aromaticity and hydrophobicity, greater porosity, and greater thermal stability than HC_dw. The Langmuir isotherm model reported maximum adsorption capacity (Q_max) of CV dye removal for HC_op (207.16 mg g^?1) was 1.5 times higher than the HC_dw (137.85 mg g^?1). While HC_op had a two-fold higher Q_max of TC removal (68.25 mg g^?1) than HC_dw (33.61 mg g^?1). Overall, the optimization of HCL-acid assisted HTC of SB was successful in producing hydrochar with good adsorption efficiency.     

Elimination of crystal violet from synthetic medium by adsorption using unmodified and acid-modified eucalyptus leaves with MPR and GA application

The aim of this investigation concerns the elimination by batch adsorption method of a primary (cationic) textile dye (Crystal Violet) from the synthetic medium, using raw and acid-modified eucalyptus leaves. Parametric studies, such as pH (2–10), unmodified and acid-modified eucalyptus leaves dose (1–10 g L^?1), time (5–300 min), and initial strength of CV (10–300 mg L^?1) are performed on the elimination of Crystal Violet from the Synthetic Medium. The R–P model gives the maximum coefficient of correlation (R² = 0.99), which denotes the best fitting isotherms with the investigational data from the other isotherms. The maximal capacity of adsorption is 141 mg g^?1 for Crystal Violet (CV) on PEUL at 25 °C and pH7. The kinetics study of the CV elimination signifies the pseudo 2nd order kinetics model gives the acceptable fitting rate equation (R² = 0.99) with the investigational data. Intraparticle diffusion model, IPD implies it's not only the rate-limiting step. The overall outcome recommends eucalyptus leaves probably utilized as a low-cost environment-friendly adsorbent for the de-pollution of effluents laden with basic (cationic) textile dye (CV). MPR and GA application on experimental data correctly predicted the removal percentage.     

Kinetic and isotherm studies on adsorptive removal of sulfates by cotton shell derived biochar: Recovery of sulfates from marcasite soil

This work illustrates the potential applications of the raw cotton shell (RCS) and cotton shell biochar (CSB) in the remediation of sulfate contaminants from aqueous solvents. Comprehensively, optimal batch and adsorption kinetics of sulfate by RCS and CSB were intensively analyzed and determined by varying the adsorption parameters. For RCS, the optimal series of parameters were at (pH-7, sulfate conc-150 mgL^?1, adsorbent dose- 0.5 g and time-150 min). While for CSB optimum conditions were at (pH-9.8, sulfate conc-100 mgL^?1, dosage- 0.1 g and time-90 min). The maximum adsorption efficiency for both RCS and CSB was achieved at 86.47% and 90.77%, respectively. Sulfate adsorption by RCS and CSB was examined by isotherm models and kinetic studies. The data are best suited to the Langmuir isotherm model with the highest RCS and CSB sulfate adsorption capability of 61.35 and 153.85 mg g^?1 and followed pseudo-second-order kinetics. Box-Behnken design (BBD) based response surface methodology (RSM) model-based analysis of variance test has demonstrated optimum conditions and sulfate adsorption by both RCS and CSB. The recovery studies on sulfates from marcasite soil were evaluated at different doses of RCS and CSB. This study provides insights into the usage of the developed process towards the circular economy of the sulfates.     

Functional biobased resin from a blend of tannin and crude black liquor and its application as an adsorbent for dexamethasone and indomethacin removal

A novel route is proposed to synthesize a functional biobased resin and its carbonized counterpart by sol-gel polymerization of a blend of tannin and crude Kraft black liquor. The potential of the synthesized biomaterial as adsorbents for dexamethasone and indomethacin removal from contaminated water was also evaluated. The characterization points out the great variety of surface functional groups, promoting different adsorbent-adsorbate interfacial interactions. As a result, the diversified functional groups favor the adsorption by electrostatic interactions, hydrogen bonds, and π-π interactions. Moreover, the thermal treatment decreased the functionality and oxygenated groups of the carbonized counterpart, increasing the hydrophobic interactions. It also increased the specific area of the material (2–98 m² g^?1) and the average pore size diameter (1.6–4.2 nm). Consequently, the carbonized counterpart exhibits superior adsorption of the model pollutants. The adsorption of dexamethasone occurred in multilayers, whose maximum adsorption capacity obtained experimentally were 11.38 mg g^?1 and 22.22 mg g^?1 for resin and the carbonized resin. Furthermore, the study concerning the adsorption of indomethacin showed that the indomethacin concentration must be controlled to optimize the adsorption process and avoid precipitation. Finally, the equilibrium studies disclosed an atypical isothermal profile, which is hardly found in the literature. Therefore, the ability to remediate the pollutants demonstrates this novel material potential for future application in water remediation technologies.     

Selective adsorption for Ag (I) from wastewater by carbon-magnetic fly ash beads modified with polydopamine and thiourea

A magnetic adsorbent was prepared by polydopamine coating and thiourea grafting on carbon-modified discarded fly ash magnetic beads (TPCMFA). The successfully preparation of the TPCMFA was supported by SEM image, XRD, FT-IR and Raman spectroscopy. Batch adsorption experiments reveal that the adsorption of silver ions on this magnetic sorbent TPCMFA agreed with the Langmuir isotherm model, with a maximum absorbability of 94.94 mg g^-1. Kinetics data revealed that the adsorption of silver ions on TPCMFA conform to a pseudo-second-order. The TPCMFA achieved remarkable selectivity for Ag (I) that was almost five times higher than that for ions of copper, zinc and nickel. After three cycles, the adsorption capacity of TPCMFA remained at 93.5% of the adsorption capacity of the initial material. These results show that this new magnetic adsorbent prepared from discarded fly ash magnetic beads has promising commercial prospects.     

A sustainably produced hydrochar from pomegranate peels for the purification of textile contaminants in an aqueous medium

Hydrothermal Carbonization presents an easy, inexpensive, and eco-friendly method to convert waste from natural resources into sustainable materials. This study used the Hydrothermal Carbonization (HTC) approach to make hydrochar from locally available pomegranate peels. Several analytical tools were employed for its characterization, including elemental analysis, X-ray Diffraction, micro-Raman, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Textual analysis, pH_pzc, and Boehm titration. The produced hydrochar performed well in removing cationic dye Basic Red 46 (BR46) from an aqueous medium, adsorbing 286.90 and 367.72 mg g^?1 within only 5 and 60 min, respectively, at ideal circumstances. The Freundlich model was the most appropriate for the equilibrium data, whilst the pseudo-second-order model was found closest to the kinetic data (R² = 0.980; Δqe = 7.934%). Per the thermodynamic study, the dye adsorption was spontaneous (ΔG° < 0) and endothermic (ΔH° = 32.777 kJ mol^?1). Furthermore, the prepared hydrochar (HCPP) has revealed good reusability, as it can be reused up to five times without losing its effectiveness. In summary, the outcomes obtained revealed that HCPP could be an effective and eco-friendly adsorbent for the treatment of colored wastewater.     

Defluoridation of water using adsorbent derived from the Labeo rohita (rohu) fish scales waste: Optimization,isotherms, kinetics,and thermodynamic study

Fluoride ions have more affinity towards chitosan material. Fish scales waste is chitosan material generated in abundance in fish markets with virtually no value. The present research attempts to convert this waste to useful adsorbent which can remove fluoride from water. A novel adsorbent is thus developed from the Labeo rohita (rohu) fish scales waste giving thermal treatment for removal of fluoride from water using the batch study of adsorption. Taguchi optimization approach with L₁₆ orthogonal array was adopted to optimize the process parameters for achieving the maximum removal of fluoride. Using ANOM, pH 3; initial F^? concentration 5 mg.L^?1; mixing time 90 min; adsorbent dose 8 g.L^?1 and temperature 303 ^OK were obtained as optimum values providing a maximum fluoride reduction of 93.32%. Adopting ANOVA, the percentage contribution of each process parameter in descending order of sequence is initial F^? concentration 72.44%> pH 20.61% > temperature 2.96% > adsorbent dose 2.45% > contact time 1.55%. The fluoride sorption onto fish scales adsorbent was best fitted with the pseudo-second-order kinetic model and follows the Freundlich isotherm (K_F = 0.865, 1/n = 0.407) model. Thermodynamic parameters (ΔS = ?6.32 J mol^?1.K^?1, and ΔH = ?2.02 kJ mol^?1) suggested a spontaneous, exothermic nature of adsorption and indicates a physiosorption mechanism on a heterogeneous material. SEM and FTIR analysis for surface morphology showed the presence of hydroxyl functional groups is responsible for fluoride sorption. In the regeneration studies, the F ^– exhausted adsorbent was eluted with 0.1 N NaOH and rinsed with distilled water to prepare the adsorbent for the next cycle. The study indicates the removal of fluoride from water onto fish scales adsorbent is quite feasible, cost-effective, recyclable, and better utilization of locally available waste material into useful adsorbent for defluoridation of water.     

Preparation and characterization of a novel functionalized agricultural waste-based adsorbent for Cu2+ removal: Evaluation of adsorption performance using response surface methodology

In this study, it was aimed to the improvement of adsorption capability with a novel modification method based on increasing surface activity of flaxseed waste (FW), an agricultural waste product, and the investigation of its usability as an effective adsorbent for Cu²⁺ removal. The modification method involves functionalization of FW with iron by adding FeCl₃ to medium in presence of N, N-Dimethyl-formamide, poly (N-vinyl-pyrrolidone), and hexamethylenetetramine. The effect of parameters was investigated by conventional univariate analysis. In addition, Response Surface Methodology (RSM) based on multivariate analysis was used to improve the performance of Cu²⁺ adsorption onto iron-modified flaxseed waste (M ? FW). Cu²⁺ removal efficiency was achieved as 91.46% ± 2.34 (N = 2) at an equilibrium time of only 15 min under determined optimum conditions as Co: 75 ppm, pH: 4.7, and m: 0.23 g. RSM was successfully applied for the prediction of adsorption. Adsorption nature was as a single-layer adsorption with a maximum adsorption capacity (Q_max) of 7.64 mg/g. The adsorption mechanism, determined to be chemically controlled, an exothermic and non-spontaneous process. Furthermore, pH-dependent adsorption showed that electrostatic interactions between M ? FW and Cu²⁺ ions play an important role in adsorption mechanism. The results of characterization studies showed that a large surface area was provided with increased porosity of structure and desired changes occurred in target functional structures with modification. Moreover, modification and reusability of M ? FW were evaluated in terms of overall sustainability and waste management. The results indicated that M ? FW has potential for usability to remove heavy metals like Cu²⁺ in environmental remediation applications.     

Adsorption properties of magnetic sodium ferrosilicate/carboxymethyl chitosan composite with more functional groups and surface negative potential

The carboxymethyl chitosan and sodium ferrosilicate were successfully combined and magnetized by the hydrothermal method, and then citric acid was used as a dispersant to further modify the composite material, effectively avoiding the aggregation effect of the material. The composite material showed a large adsorption capacity (515.0 mg g^?1) for methylene blue (MB). The composite materials were characterized by XRD, SEM, EDX, FTIR, VSM, BET, Zeta and other characterization methods. The results showed that the composite with citric acid as dispersant had a larger specific surface area and a richer pore structure, and the negative potential on the surface of the composite material made it more conducive for the adsorption of cationic dye MB. The Langmuir model and the pseudo second-order kinetic model were used to explain the process of composite material adsorption of MB. In addition, the composite material had good recycling and reuse characteristics, and had great application value in the field of wastewater treatment.     

Production of mesoporous and thermally stable silica powder from low grade kaolin based on eco-friendly template free route via acidification of appropriate zeolite compound for removal of cationic dye from wastewater

The amorphous silica with the extended surface area was fabricated for the methylene blue (MB) adsorption. In the first step, the zeolite compounds were produced hydrothermally from the transformation of a low grade kaolin, containing quartz by changing NaOH concentration, temperature, and reaction time based on the central composite design method (CCD). In the second step, the mesoporous silica powders were fabricated by the acid treatment of obtained zeolite compounds at 80 °C. Although quartz was deleted in the alkali concentrated solutions, > 4 mol L^?1, hydroxysodalite, and cancrinite mixtures were formed at the higher temperatures, and longer reaction times. The acidification of these mixtures led to the formation of silica powders with the unacceptable adsorption yield. The adsorptive performance of silica produced from the powder predominantly containing hydroxysodalite was comparable with those fabricated from the other zeolite compounds. The average pore size, and specific surface area of produced SiO₂ were 4.3 nm, and 637 m² g^?1 respectively, which provided a large number of functional groups in the surface of particles, leading to the strong affinity towards MB in the neutral condition with a maximal adsorption capacity of 135 mg g^?1. The used adsorbent can be thermally regenerated without significant losing the adsorption efficiency, which is of great importance from engineering view point. The convenient fabrication from an inexpensive resource according to a template-free route plus reusability facilitate the application of obtained silica in the treatment of wastewaters contaminated with the cationic dyes.     

From green biowaste to water treatment applications: Utilization of modified new biochar for the efficient removal of ciprofloxacin

Water pollution caused by antibiotics is a serious environmental problem in recent years. Using biochar to remove such pharmaceutical pollutants has recently emerged as a promising option. After H₃PO₄ modification, a new waste-based biochar (MPCWSB500) from sour cherry stalk was successfully synthesized to remove ciprofloxacin (CFX) from aquatic media, and modification of feedstock has significantly improved the adsorption capacity of biochar. MPCWSB500 is suitable for both batch and continuous treatment systems. The CFX sorption was systematically studied using various kinetics and isotherm models. The surface characteristics of the modified biochar and the possible CFX?biochar interactions were investigated by BET, FT?IR, and SEM?EDX analysis. Short operation time, high sorption capacity (410.06 mg g^?1), and nearly 100% removal efficiency were recorded as significant findings at optimum experimental conditions (pH: 6.3, contact time: 40 min, MPCWSB500 dose: 15 mg). Furthermore, the modified biochar exhibited more than 95% CFX removal efficiency in continuous mode at all flow rates (1–10 mL min^?1). Its sorption performance was minimally affected by the presence of Cl^?, K⁺, Na⁺, and NO₃^? ions in the adsorption medium. In addition, up to 5 sorption-desorption cycles, biochar regeneration and recycling produced satisfactory results. The proposed biochar was also successfully used to remove CFX from simulated hospital wastewater and synthetic urine samples. These features are all important advantages for its real applications. Overall, our research offers a practical approach for removing CFX from the polluted aquatic environment.     

Particles emitted from indoor combustion sources: size distribution measurement and chemical analysis

This study is primarily focused toward measuring the particle size distribution and chemical analysis of particulate matter that originates from combustion sources typically found in Indian urban homes. Four such sources were selected: cigarette, incense stick, mosquito coil, and dhoop, the latter being actually a thick form of incense stick. Altogether, seven of the most popular brands available in the Indian market were tested. Particle size distribution in the smoke was measured using a scanning mobility particle sizer, using both long and nano forms of differential mobility analyzer (DMA), with readings averaged from four to six runs. The measurable particle size range of the nano DMA was 4.6?nm to 157.8?nm, whereas that of the long DMA was 15.7?nm to 637.8?nm. Therefore, readings obtained from the long and the nano DMA were compared for different brands as well as for different sources. An overlap was seen in the readings in the common range of measurement. The lowest value of peak concentration was seen for one brand of incense stick (0.9?×?10⁶?cm^?3), whereas the highest (7.1?×?10⁶?cm^?3) was seen for the dhoop. Generally, these sources showed a peak between 140 and 170?nm; however, 2 incense stick brands showed peaks at 79?nm and 89?nm. The dhoop showed results much different from the rest of the sources, with a mode at around 240?nm. Chemical analysis in terms of three heavy metals (cadmium, zinc, and lead) was performed using graphite tube atomizer and flame-atomic absorption spectrophotometer. Calculations were made to assess the expected cancer and noncancer risks, using published toxicity potentials for these three heavy metals. Our calculations revealed that all the sources showed lead concentrations much below the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) level. One of the two mosquito coil brands (M₂) showed cadmium concentrations two times higher than the California Environmental Protection Agency (Cal EPA) reference exposure level (REL). The latter also showed the highest carcinogenic risks of 350 people per million population. The amount of zinc obtained from the sources, however, was found to be quite below the standard limits, implying no risk in terms of zinc.     

Low-cost silica xerogels as potential adsorbents for ciprofloxacin removal

Ciprofloxacin, a second generation fluoroquinolone antibiotic, is one of the top pharmaceutical contaminants in water and many approaches have been developed for the removal of ciprofloxacin in wastewater. In this study, ciprofloxacin adsorption is carried out using a low-cost silica xerogel synthesized by a simple sol-gel method. The effect of pH, contact time, initial concentration of ciprofloxacin and temperature on the adsorption of ciprofloxacin by the silica xerogel is investigated. At optimum adsorption conditions, the experimental data fits well to a Langmuir isotherm and a pseudo-second-order kinetic model. The maximum ciprofloxacin adsorption capacity is determined as 24.45 mg g^?1. Thermodynamic parameters show that ciprofloxacin adsorption by the silica xerogel is a spontaneous endothermic process. Moreover, reusability experiments reveal that the silica xerogel can be effectively used several times for ciprofloxacin adsorption. The promising results indicate that the silica xerogel can be regarded as potential adsorbent for ciprofloxacin removal.     

Phenol removal from wastewater using low-cost natural bioadsorbent neem (Azadirachta indica) leaves: Adsorption study and MLR modeling

This research aims to experiment with the potential of neem (Azadirachta indica) leaves for phenol adsorption. Morphology, functional groups, etc. characterize the adsorbent. Batch studies are conducted at pH (2–7), dose (7–12 g/L), time (60–360 min), initial concentration (100–500 mg/L), and temperature (30–50 °C). Maximum 97.5% phenol is removed when pH, dose, time, temperature, and phenol concentration is 3, 10 g/L, 240 min, 30 °C and 100 mg/L, respectively. Experimental results are supported by pseudo-second-order (r² = 0.99999). Kinetic testing is supported by adsorption mechanisms developed by Elovich, Reichenberg, Boyd, Furusawa and Smith, and Fick models. Freundlich model (r² = 0.99648) is fitted well compare to other models. Sorption energy (0.5288 kJ/mol) supports physical adsorption. Thermodynamics has suggested for a non-random, exothermic, and spontaneous process. The multiple linear progressing (MLR) modeling has successfully predicted the removal percentage. Desorption with ethanol has revealed 58.5% phenol removal potential. Safe disposal of the used adsorbent is recommended by incineration. The scale-up design has demonstrated that 27.925 kg adsorbent is required for 1000 L wastewater to reduce phenol from 100 ppm to 0.06 ppm in two stages. The novel study concludes that the natural, low-cost bio-adsorbent neem leaves can suitably be used in the refineries and other allied chemical industries for phenol remediation.     

Production of nZVI–Cl nanocomposite as a novel eco–friendly adsorbent for efficient As(V) ions removal from aqueous media: Adsorption modeling by response surface methodology

By combination of the nano zero–valent iron (nZVI) nanoparticles and clinoptilolite (Cl) natural zeolite and by chemical reduction method, the nZVI–Cl nanocomposite was produced. The physical and chemical characteristics of the produced nanocomposite were examined using FE–SEM, EDX, VSM and zeta potential analyses and its fine structure was confirmed. The produced nanocomposite was applied for efficient As(V) heavy metal ions removal from aqueous media as a novel eco–friendly adsorbent. The adsorption process was optimized using a minimum number of designed experiments by Design–Expert software using central composite design (CCD) and response surface methodology (RSM) and the adsorption optimum conditions were determined as solution pH of 4, nZVI–Cl dosage of 1 g L^?1 and As(V) concentration of 50 mg L^?1 by the numerical optimization of the software. In these conditions, the removal efficiency was 88.10% and desirability parameter was 0.986. The adsorption kinetic study showed that the chemisorption effectively controls the adsorption process by a better fit of pseudo–second order model with the experimental data. The adsorption isotherms study demonstrated that the Langmuir model had the best fit with the experimental data, proving homogeneous surface of nZVI–Cl adsorbent and monolayer adsorption of As(V) ions on it. The adsorption thermodynamic study illustrated that the adsorption is thermodynamically spontaneous and exothermic in nature. Also, the adsorbent reusability test verified the adsorbent stability after five consecutive adsorption–desorption cycles without a tangible reduction in removal efficiency.     

Efficient Adsorption of Deoxynivalenol by Porous Carbon Prepared from Soybean Dreg

A novel porous carbon adsorbent for the removal of deoxynivalenol was prepared from soybean dreg (SD). The new material was characterized by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) analysis, N₂ adsorption/desorption measurement techniques, X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The specific surface area of the SDB-6-KOH was found to be 3655.95 m² g⁻¹, the pore volume was 1.936 cm³ g⁻¹ and the average pore size was 2.125 nm. The high specific surface area and effective functional groups of the carbon material promoted the adsorption of deoxynivalenol. By comparing the adsorption effect of SDB-6-X prepared with different activators (X: KOH, K₂CO₃, KHCO₃), SDB-6-KOH had the highest adsorption capacity. The maximum adsorption capacity of SDB-6-KOH to deoxynivalenol was 52.9877 µg mg⁻¹, and the removal efficiency reached 88.31% at 318 K. The adsorption kinetic and isotherm data were suitable for pseudo-second-order and Langmuir equations, and the results of this study show that the novel carbon material has excellent adsorptive ability and, thus, offers effective practical application potential for the removal of deoxynivalenol.     

Enhancement of CO2 adsorption on natural zeolite,modified clinoptilolite with cations,amines and ionic liquids

The modification of clinoptilolite as a natural zeolite via a simple route was carried out for CO₂ adsorption. Cation exchange with Li⁺, Mg^2+, and Ca²⁺, amine modification using monoethanolamine (MEA), triethanolamine (TEA) and hexyl amine, and ionic liquid modification using [bmim]X (X = PF₆?, NO₃?, Br?, Cl?, and bmim = 1-Butyl-3-methylimidazolium) were performed in a different amount of the modifiers. The samples were characterized by several methods (XRD, FT-IR, BET, and SEM), and adsorbed CO₂ was evaluated utilizing adsorption isotherm at a wide range of pressure. The results showed enhancement in CO₂ adsorption capacity for all the samples and 4.18, 3.58, and 4.35 times increase in CO₂ adsorption were obtained where clinoptilolite/Li⁺, clinoptilolite/2% MEA and clinoptilolite/5% [bmim]PF₆ were used as adsorbent at 4 bar pressure of CO₂, respectively.