Enhancing fluoride ion removal from aqueous solutions and glass manufacturing wastewater using modified orange peel biochar magnetic composite with MIL-53.

In this study, we developed new adsorbents derived from orange peel biochar (BCOP) and enhanced them with CoFe2O4 magnetic nanoparticles (BCOP/CoFe2O4) and MIL-53(Al) (BCOP/CoFe2O4/MIL-53(Al)). These adsorbents were utilized to remove fluoride (FL) ions from aqueous solutions. We analyzed the properties of these adsorbents using a range of techniques, including FTIR, XRD, SEM, EDX-Map, VSM, Raman spectroscopy, and BET. Our findings indicate that the components interact effectively with one another. Specifically, the BCOP/CoFe2O4/MIL-53(Al) sample exhibited a specific surface area of 196.430 m2/g and a magnetic saturation value of 9.704 emu/g. The maximum FL ion adsorption capacities for BCOP, BCOP/CoFe2O4, and BCOP/CoFe2O4/MIL-53(Al) were 7.618, 16.330, and 37.320 mg/g, respectively, indicating that the modifications significantly enhanced the adsorption capacity. The optimum fluoride ion removal rates using BCOP, BCOP/CoFe2O4, and BCOP/CoFe2O4/MIL-53(Al) were 97.88%, 98.23%, and 99.06%, respectively, at adsorbent doses of 2.5, 1.5, and 0.8 g/L, contact times of 90, 70, and 50 minutes, pH 4, temperature 50°C, and a FL concentration of 10 mg/L. Thermodynamic studies revealed that the adsorption process was spontaneous and endothermic, with increased randomness between the adsorbent and fluoride ions. Kinetic analyses showed that fluoride ion adsorption by BCOP/CoFe2O4/MIL-53(Al) followed a pseudo-second-order (PSO) model, while BCOP and BCOP/CoFe2O4 followed a pseudo-first-order (PFO) model. Additionally, the equilibrium data for fluoride ion adsorption on BCOP/CoFe2O4/MIL-53(Al) adhered to the Freundlich model, whereas the other samples conformed to the Langmuir model. The study evaluates the effectiveness of BCOP, BCOP/CoFe2O4, and BCOP/CoFe2O4/MIL-53(Al) in removing FL ions from glass manufacturing wastewater, highlighting the superior performance of the magnetic composite due to its enhanced surface area and functional groups. Notably, the adsorbents demonstrated good regenerative capabilities, maintaining high performance over multiple adsorption cycles.

Carboxymethyl cellulose/activated carbon/hydroxyapatite composite adsorbent for remediation of methylene blue from water media.

In the present study, activated carbon (AC), activated carbon/hydroxyapatite (AC/HAp), and carboxymethyl cellulose/activated carbon/hydroxyapatite (CMC/AC/HAp) composite adsorbents were prepared to remediation of methylene blue (MB) from water media. The pyrolysis method used the Pine cone as a natural precursor to synthesize AC. FTIR, XRD, Raman, BET, TEM, and SEM-Dot mapping techniques were applied to characterize synthesized adsorbents. Experimental results demonstrated that the maximum removal efficiency of AC, AC/HAp, and CMC/AC/HAp adsorbents under optimum conditions of pH 8, adsorbent dose 1 g/L, contact time 60 min, initial concentration 10 mg/L, and temperature 25 °C was computed to be 98.75, 98.86, and 98.93 %, respectively. Kinetic and equilibrium data were well-fitted with pseudo-second-order and Langmuir models, respectively. The maximum monolayer adsorption capacity of AC, AC/HAp, and CMC/AC/HAp was determined to be 40, 44.248, and 43.86 mg/g, respectively. FTIR results showed that hydrogen bonding and electrostatic interactions are the main mechanisms of the adsorption process. Results of the thermodynamic study showed that the adsorption process is spontaneous and exothermic. Finally, AC, AC/HAp, and CMC/AC/HAp composite adsorbents can be used as promising adsorbents for the remediation of MB from wastewater.

Effectiveness of polyacrylamide-g-gelatin/ACL/Mg-Fe LDH composite hydrogel as an eliminator of crystal violet dye.

Cationic synthetic dyes are one of the hazards in aqueous solutions that can affect the health of humans and living organisms. In the current work, polyacrylamide (PAM)-g-gelatin hydrogel and modified PAM-g-gelatin hydrogel using activated carbon of Luffa cylindrica (ACL) and ACL/Mg-Fe LDH were applied to eliminate crystal violet (CV), a cationic dye, from water media. The hydrogels were synthesized using free radical polymerization approach, and the hydrogels were characterized using FTIR, XRD, TGA-DTG, BET, SEM, and EDX-Map. The surface area of ACL, ACL/Mg-Fe LDH, PAM-g-gelatin, PAM-g-gelatin/ACL, and PAM-g-gelatin/ACL/Mg-Fe LDH were 99.71, 141.99, 0.74, 1.47, and 1.65 m2/g, respectively, which shows that the presence of ACL and ACL/Mg-Fe LDH improved the area of the hydrogels. The maximum abatement of CV using PAM-g-gelatin (92.81%), PAM-g-gelatin/ACL (95.71%), and PAM-g-gelatin/ACL/Mg-Fe LDH (98.25%) was obtained at pH = 9, temperature 25 °C, 10 mg/L CV, 60 min time, and adsorber dose of 2 g/L (for PAM-g-gelatin) and 1.5 g/L (other samples). The value of thermodynamic factors confirmed that the abatement process is exothermic and spontaneous. The kinetics data followed the pseudo-second kinetic (PSO) model. The Langmuir isotherm model had a more remarkable ability to describe the equilibrium data. The maximum adsorption capacity for PAM-g-gelatin, PAM-g-gelatin/ACL, and PAM-g-gelatin/ACL/Mg-Fe LDH was determined 35.45, 39.865, and 44.952 mg/g, respectively. Generally, the studied hydrogels can eliminate dyes from wastewater and be used as effective adsorbers.

Amendment of Sargassum oligocystum bio-char with MnFe2O4 and lanthanum MOF obtained from PET waste for fluoride removal: A comparative study.

The use of biomass and waste to produce adsorbent reduces the cost of water treatment. The bio-char of Sargassum oligocystum (BCSO) was modified with MnFe2O4 magnetic particles and La-metal organic framework (MOF) to generate an efficient adsorbent (BCSO/MnFe2O4@La-MOF) for fluoride ions (F-) removal from aqueous solutions. The performance of BCSO/MnFe2O4@La-MOF was compared with BCSO/MnFe2O4 and BCSO. The characteristics of the adsorbents were investigated using various techniques, which revealed that the magnetic composites were well-synthesized and exhibited superparamagnetic properties. The maximum adsorption efficiencies (BCSO: 97.84%, BCSO/MnFe2O4: 97.85%, and BCSO/MnFe2O4@La-MOF: 99.36%) were achieved under specific conditions of pH 4, F- concentration of 10 mg/L, and adsorbent dosage of 3, 1.5, and 1 g/L for BCSO, BCSO/MnFe2O4, and BCSO/MnFe2O4@La-MOF, respectively. The results demonstrated that the experimental data adheres to a pseudo-second-order kinetic model. The enthalpy, entropy, and Gibbs free energy were determined to be negative; thus, the F- adsorption was exothermic and spontaneous in the range of 25-50 °C. The equilibrium data of the process exhibited conformity with the Langmuir model. The maximum adsorption capacities of F- ions were determined as 10.267 mg/g for BCSO, 14.903 mg/g for the BCSO/MnFe2O4, and 31.948 mg/g for BCSO/MnFe2O4@La-MOF. The KF and AT values for the F- adsorption were obtained at 21.03 mg/g (L/mg)1/n and 100 × 10+9 L/g, indicating the pronounced affinity of the BCSO/MnFe2O4@La-MOF towards F- than other samples. The significant potential of the BCSO/MnFe2O4@La-MOF magnetic composite for F- removal from industrial wastewater, makes it suitable for repeated utilization in the adsorption process.

Efficacious adsorption of divalent nickel ions over sodium alginate-g-poly(acrylamide)/hydrolyzed Luffa cylindrica-CoFe2O4 bionanocomposite hydrogel.

Existing Ni2+ heavy metal ions in an aqueous medium are highly hazardous for living organisms and humans. Therefore, designing low-cost adsorbents with enhanced effectiveness is essential for removing nickel ions to safeguard public health. In this study, a novel green nanocomposite hydrogel was synthesized through the free radical solution and bulk polymerization method, and its capability to remove divalent nickel ions from aqueous media was examined. The bionanocomposite hydrogel named as SA-g-poly(AAm)/HL-CoFe2O4 was produced by grafting polyacrylamide (AAm) onto sodium alginate (SA) in the presence of a magnetic composite recognized as HL-CoFe2O4, where HL represents hydrolyzed Luffa Cylindrica. By employing FT-IR, XRD, VSM, SEM, EDX-Map, BET, DLS, HPLC, and TGA techniques, morphological evaluation and characterization of the adsorbents were carried out. The performance of the adsorption process was studied under varying operational conditions including pH, temperature, contact duration, initial concentration of pollutant ions, and adsorbent dosage. HPLC analysis proved the non-toxic structure of the bionanocomposite hydrogel. The number of unreacted acrylamide monomers within the hydrogel matrix was measured at 20.82 mg/kg. The optimum conditions was discovered to be pH = 6, room temperature, adsorbent dosage of 1 of g.L-1, initial Ni2+ concentration of 10 mg.L-1, and contact time of 100 min, and the maximum adsorption efficiency at optimal state was calculated as 70.09, 90.25, and 93.83 % for SA-g-poly (AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples, respectively. Langmuir isotherm model was in good agreement with the experimental data and the maximum adsorption capacity of SA-g-poly(AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples was calculated to be 31.37, 43.15, and 45.19 mg.g-1, respectively. The adsorption process, according to kinetic studies, follows a pseudo-second-order kinetic model. Investigations on thermodynamics also demonstrated that the process is exothermic and spontaneous. Exploring the interference effect of co-existing ions showed that the adsorption efficiency has decreased with concentration enhancement of Ca2+ and Na+ cations in aqueous medium. Furthermore, the adsorption/desorption assessments revealed that after 8 consecutive cycles, there had been no noticeable decline in the adsorption effectiveness. Finally, actual wastewater treatment outcomes demonstrated that the bionanocomposite hydrogel successfully removes heavy metal pollutants from shipbuilding industry effluent. Therefore, the findings revealed that the newly fabricated bionanocomposite hydrogel is an efficient, cost-effective, easy-separable, and green adsorbent that could be potentially utilized to remove divalent nickel ions from wastewater.

Photodegradation of ibuprofen laden-wastewater using sea-mud catalyst/H2O2 system: evaluation of sonication modes and energy consumption.

The main goal of the current investigation was to decontaminate ibuprofen (IBP) from hospital wastewater using sea mud as an H2O2 activator. Sea sludge was converted into catalysts at different temperatures and residence times in furnaces, and then tested in the removal of IBP, and the most efficient ones were reported for the production of catalysts. The catalyst was optimized at 400 °C and 3 h. SEM-mapping, FTIR, EDX, BET, and BJH experiments were used to characterize the catalyst. Experiments were done at two pulsed and continuous ultrasonication modes in a photoreactor, and their efficiencies were statistically compared. The designed variables included IBP concentration (10-100 mg/L), the catalyst concentration (0-3 g/L), pH (4-9), and time (10-90 min). The oxidation process had the maximum efficiency at pH 4, treatment time of 60 min, catalyst quantity of 5 g/L, and IBP content of 50 mg/L. The catalyst was recycled, and in the fifth stage, the removal efficiency of IBP was reduced to 50%. The amount of energy consumed for treating IBP laden-wastewater using the evaluated catalyst in two modes of continuous and pulsed ultrasonic was calculated as 102 kW h/m3 and 10 kW h/m3, respectively. IBP oxidation process was fitted with the first-order kinetic model. The system can be proposed for purifying hospital and pharmaceutical wastewaters.

Decontamination of Fuchsin dye by carboxymethyl cellulose-graft-poly(acrylic acid-co-itaconic acid)/carbon black nanocomposite hydrogel.

In the present work, carboxymethyl cellulose (CMC) was used to develop hydrogels as adsorbents for wastewater treatment applications due to its surface functionality and modifiable characteristics. Hydrogels (Hyd) were synthesized by grafting copolymers of acrylic acid (AA) and itaconic acid (IA) onto the CMC backbone by free radical polymerization method in order to remediate Fuchsin from aqueous solution. The presence of CMC in copolymer hydrogel of AA and IA (Poly(AA-co-IA)) up to 14.29 wt% enhances equilibrium swelling and removal efficiency. Different novel nanocomposite hydrogel samples were prepared by varying weight percentages of carbon black (CB) nanoparticles in the range of 0 to 12.5 wt%. The addition of CB up to 5 wt% enhanced the swelling and removal efficiency of the Hyd. Brunauer-Emmett-Teller (BET) test gave the surface area of 0.615, and 0.890 m2/g for Hyd and Hyd/CB, respectively, indicating that incorporation of CB led to a significant increase in Hyd surface area. The Maximum removal efficiency of Fuchsin under the optimum conditions was obtained to be 83.33, 93.54, and 98.76 % for Poly(AA-co-IA), Hyd, and Hyd/CB, respectively. The kinetic study showed that the pseudo-second-order is the best-fitted model. Isotherm studies showed that equilibrium data have a good fitness with the Langmuir model with R2 of 0.978, 0.992, and 0.982 for Poly(AA-co-IA), Hyd, and Hyd/CB, respectively. The Langmuir model gave an adsorption capacity of 26.99, 31.6, and 33.75 mg/g for Poly(AA-co-IA), Hyd, and Hyd/CB, respectively. Also, the value of n and RL parameters demonstrated that the adsorption process is physical and favorable for adsorbents. The study of thermodynamic parameters illustrated that the adsorption of Fuchsin using adsorbents is a spontaneous, exothermic, and entropy-decreasing process. Regeneration study showed that CMC-based hydrogels have higher performance in ad(de)sorption cycles than Poly(AA-co-IA) and the addition of CB to the Hyd matrix enhances reusability. Overall, Hyd and Hyd/CB can be used as promising adsorbents for the remediation of Fuchsin due to high swelling and adsorption capability.

Sono-Photocatalytic Activity of Cloisite 30B/ZnO/Ag2O Nanocomposite for the Simultaneous Degradation of Crystal Violet and Methylene Blue Dyes in Aqueous Media.

A new nanocomposite based on Cloisite 30B clay modified with ZnO and Ag2O nanoparticles (Cloisite 30B/ZnO/Ag2O) was synthesized as an effective catalyst in the sono-photocatalytic process of crystal violet (CV) and methylene blue (MB) dyes simultaneously. The characteristics and catalytic activity of Cloisite 30B/ZnO/Ag2O nanocomposite were investigated under different conditions. The specific active surface for Cloisite 30B/ZnO/Ag2O nanocomposite was 18.29 m2/g. Additionally, the catalytic activity showed that Cloisite 30B/ZnO/Ag2O nanocomposite (CV: 99.21%, MB: 98.43%) compared to Cloisite 30B/Ag2O (CV: 85.38%, MB: 83.62%) and Ag2O (CV: 68.21%, MB: 66.41%) has more catalytic activity. The catalytic activity of Cloisite 30B/ZnO/Ag2O using the sono-photocatalytic process had the maximum efficiency (CV: 99.21%, MB: 98.43%) at pH 8, time of 50 min, amount of 40 mM H2O2, catalyst dose of 0.5 g/L, and the concentration of 'CV + MB' of 5 mg/L. The catalyst can be reused in the sono-photocatalytic process for up to six steps. According to the results, •OH and h+ were effective in the degradation of the desired dyes using the desired method. Data followed the pseudo-first-order kinetic model. The method used in this research is an efficient and promising method to remove dyes from wastewater.

Adsorption ability evaluation of the poly(methacrylic acid-co-acrylamide)/cloisite 30B nanocomposite hydrogel as a new adsorbent for cationic dye removal.

The performance of poly(methacrylic acid-co-acrylamide)/Cloisite 30B nanocomposite (poly(MAA-co-AAm)/Cl30B) hydrogel to adsorb methylene blue (MB) dye from aqueous solutions was investigated and the adsorption efficiency was improved by incorporating Cloisite 30B nanoclays in the adsorbent structure. The hydrogels were analyzed using FTIR, XRD, TGA, and SEM analysis. The effect of adsorbent dose, temperature, initial dye concentration, contact time, and pH on the efficiency of the adsorption process was investigated. Adsorption efficiencies of 98.57 and 97.65% were obtained for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels, respectively. Kinetic study revealed that the adsorption process followed pseudo-first-order kinetic model and α-parameter values of 6.558 and 1.113 mg/g.min were obtained for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels, respectively indicating a higher ability of nanocomposite hydrogel in adsorbing MB-dye. In addition, the results of the intra-particle diffusion model showed that various mechanisms such as intra-particle diffusion and liquid film penetration are important in the adsorption. The Gibbs free energy parameter of adsorption process showed negative values of -256.52 and -84.071 J/mol.K for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels indicating spontaneous nature of the adsorption. The results of enthalpy and entropy showed that the adsorption process was exothermic and random collisions were reduced during the adsorption. The equilibrium data for the adsorption process using poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels followed Freundlich and Langmuir isotherm models, respectively. The maximum adsorption capacity values of 32.83 and 21.92 mg/g were obtained for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels, respectively. Higher adsorption capacity of nanocomposite hydrogel was attributed to the presence of Cloisite 30B clay nanoparticles in its structure. In addition, results of RL, n, and E parameters showed that the adsorption process was performed optimally and physically.

Surface magnetization of hydrolyzed Luffa Cylindrica biowaste with cobalt ferrite nanoparticles for facile Ni2+ removal from wastewater.

A novel magnetic adsorbent based on hydrolyzed Luffa Cylindrica (HLC) was synthesized through the chemical co-precipitation technique, and its potential was evaluated in the adsorptive elimination of divalent nickel ions from water medium. Morphological assessment and properties of the adsorbent were performed using FTIR, SEM, EDX, XRD, BET, and TEM techniques. The effect of pH, temperature, time and nickel concentration on the removal efficiency was studied, and pH = 6, room temperature (25 °C), contact time of 60 min, and Ni2+ ion concentration of 10 mg.L-1 were introduced as the optimal values. At optimal conditions, the removal efficiency of Ni2+ ions using HLC and HLC/CoFe2O4 magnetic composite was calculated as 96.38 and 99.13%, respectively. The adsorption process kinetic followed a pseudo-first-order model. Langmuir isotherm was suitable for modelling the experimental data of the Ni2+ adsorption. The maximum elimination capacity of HLC and HLC/CoFe2O4 samples was calculated as 42.75 and 44.42 mg g-1, respectively. Furthermore, thermodynamic investigations proved the spontaneous and exothermic nature of the process. The adsorption efficiency was decreased with increasing the content of Ca2+ and Na + cations in aqueous media. During reusability of the synthesized adsorbents, it was found that after 8 cycles, no significant decrease has occurred in the adsorption efficiency. In addition, real wastewater treatment results proved that HLC/CoFe2O4 magnetic composite has an excellent performance in removal of heavy metals pollutant from shipbuilding effluent.

Cadmium ion removal from aqueous media using banana peel biochar/Fe3O4/ZIF-67.

In the present study, banana peel waste was used as a suitable source for biochar production. The banana peel biochar (BPB) was modified using Fe3O4 magnetic and ZIF-67 nanoparticles. The modification of the BPB surface (4.70 m2/g) with Fe3O4 and Fe3O4/ZIF-67 significantly increased the specific surface of the nanocomposites (BPB/Fe3O4: 78.83 m2/g, and BPB/Fe3O4/ZIF-67: 1212.40 m2/g). The effect of pH, temperature, contact time, adsorbent dose, and concentration of Cd2+ on the efficiency of the Cd2+ adsorption was explored. Maximum adsorption efficiencies for BPB (97.76%), BPB/Fe3O4 (97.52%), and BPB/Fe3O4/ZIF-67 (99.14%) were obtained at pH 6, Cd2+ concentration of 10 mg/L, times of 80 min, 50 min, and 40 min, and adsorbent doses of 2 g/L, 1.5 g/L, and 1 g/L, respectively. Thermodynamic measurements indicated that the process is spontaneous and exothermic. The maximum capacity of Cd2+ adsorption using BPB, BPB/Fe3O4, and BPB/Fe3O4/ZIF-67 were obtained 20.63 mg/g, 30.33 mg/g, and 50.78 mg/g, respectively. The Cd2+ adsorption using magnetic nanocomposites followed the pseudo-first-order kinetic model. The results showed that studied adsorbents especially BPB/Fe3O4/ZIF-67 have a good ability to adsorb-desorb Cd2+ and clean an effluent containing pollutants.

Development of new magnetic adsorbent of walnut shell ash/starch/Fe3O4 for effective copper ions removal: Treatment of groundwater samples.

The goal of this investigation was to develop a new magnetic nanocomposite of walnut shell ash (WSA)/starch/Fe3O4 to remove Cu (II) present in groundwater samples. The desired nanocomposites were successfully synthesized by the chemical deposition method. The specific active surface area for pristine WSA and WSA/starch/Fe3O4 magnetic nanocomposites was determined to be 8.1 and 52.6 m2/g, respectively. A central composite design for the response surface method was utilized to study the influence of pH, adsorbent quantity, initial content of Cu (II), temperature, and contact time. This method showed the success of the model to design process variables and to estimate the appropriate response. The P- and F-value determined for the quadratic polynomial model showed the significance and accuracy of the proposed model in examining experimental and predicted data with R2 and Adj.R2 of 0.994 and 0.991, respectively. The Cu adsorption onto WSA and WSA/starch/Fe3O4 obeyed the Freundlich and Langmuir models, respectively. The highest Cu (II) sorption capacity of 29.0 and 45.4 mg/g was attained for WSA and WSA/starch/Fe3O4, respectively. The free energy of Gibbs had a negative value at 25-45 °C indicating that the adsorption process is spontaneous. Also, negative ΔH values for copper adsorption showed that the processes are exothermic. The kinetic adsorption data for WSA and WSA/starch/Fe3O4 followed the pseudo-second order (PSO) model. The ability of the composite adsorbent to remove copper from three groundwater samples showed that it could be reused at least 3 times with appropriate efficiency, depending on the water quality.

Application of waste chalk/CoFe2O4/K2CO3 composite as a reclaimable catalyst for biodiesel generation from sunflower oil.

This investigation aimed to produce a new composited catalyst from a waste chalk powder, a waste generated by the construction industry, to produce biodiesel from sunflower oil. The waste chalk was modified by CoFe2O4 nanoparticles and K2CO3. The surface tests showed that the obtained catalyst has been successfully synthesized with desired surface properties. The surface areas of waste chalk, waste chalk/CoFe2O4, and waste chalk/CoFe2O4/K2CO3 were determined 20.8, 77.8, and 5.8 m2/g, respectively. This indicates that the waste chalk/CoFe2O4/K2CO3 catalyst has a lower surface area due to K2CO3 being placed on the catalyst. Results showed the efficiency of RSM-CCD (R2 = 0.992) compared to ANN (R2 = 0.974). It was shown that a contact time of 180 min, a temperature of 65 °C, a waste chalk/CoFe2O4/K2CO3 mass of 2 wt%, and methanol to oil mole ratio of 15:1 gave the highest efficiency (98.87%) of biodiesel production at the laboratory conditions. The kinetic results of the process showed the energy of activation and frequency factor of 11.8 kJ/mol and 0.78 min-1, respectively. Also, the values of ΔH°, ΔS°, and ΔG° at 65 °C was calculated to be 9010.7 J/mol, -256.3 J/mol and 95.7 kJ/mol, respectively, indicating that the biodiesel production process is endothermic requiring high energy for proceeding. The generated catalyst has an efficiency of over 90% up to 6 steps of reuse. The generated biodiesel was met most of the international standard levels.

Impact of ZnO and Fe3O4 magnetic nanoscale on the methyl violet 2B removal efficiency of the activated carbon oak wood.

In the current study, activated carbon oak wood (ACOW600) and modified activated carbon using ZnO (ACOW600/ZnO) and Fe3O4 (ACOW600/ZnO/Fe3O4) nanoparticles were used to remove methyl violet 2B dye (MV2B) from aqueous solutions. ACOW was synthesized at different temperatures (300-700 °C), and then the maximum MV2B removal efficiency (92.76 %) was achieved using ACOW synthesized at 600 °C. The morphology and characteristics of ACOW600, ACOW600/ZnO, and ACOW600/ZnO/Fe3O4 were studied using surface analyzes. According to the results, the adsorbents indicated a high ability to absorb MV2B from liquid solution, and their kinetic behavior follows a pseudo-second-order kinetic. In addition, the equilibrium study revealed that the MV2B uptake by the ACOW600/ZnO/Fe3O4 magnetic nanocomposite followed the Freundlich model. In contrast, the Langmuir model described the MV2B adsorption process using ACOW600 and ACOW600/ZnO. The maximum adsorption capacity (qm) of MV2B using ACOW600, ACOW600/ZnO, and ACOW600/ZnO/Fe3O4 was determined 26.16 mg g-1, 37.05 mg g-1, and 48.59 mg g-1, respectively, indicating that modification of ACOW600 led to improve its performance in removing MV2B. The enthalpy (ΔH), entropy (ΔG), and Gibbs free energy (ΔS) parameters revealed that the decontamination of MV2B using the studied adsorbents was exothermic and spontaneous. Also, random interactions of MV2B molecules and adsorbent surfaces were reduced during the adsorption process. Textile wastewater was significantly treated by ACOW600, ACOW600/ZnO, and ACOW600/ZnO/Fe3O4 adsorbents. The recycling of the adsorbents was demonstrated that the investigated adsorbents could be re-utilized many times in the MV2B removal process.

Preparation of clinoptilolite/starch/CoFe2O4 magnetic nanocomposite powder and its elimination properties for cationic dyes from water and wastewater.

A new magnetic nanocomposite clinoptilolite (CLT)/Starch/CoFe2O4 was synthesized using co-precipitation method. The prepared magnetic composite powder was utilized for decontamination of methylene blue dye (MBD), methyl violet dye (MVD), and crystal violet dye (CVD) from water media. The BET analysis showed that CLT modification using starch and CoFe2O4 nanoparticles improved its specific surface and the amount of specific surface area for CLT, CoFe2O4, and CLT/Starch/CoFe2O4 powder was reported to be 18.82 m2.g-1, 151.4 m2.g-1, and 104.75 m2.g-1, respectively. Experimental results showed that pH 9 had a vital role in the adsorption process of all three types. Langmuir and Redlich-Petersen isotherm models were well fitted with experimental data. Also, the maximum adsorption capacity of CVD, MBD, and MVD to the desired composite was determined as 32.84 mg.g-1, 31.81 mg.g-1, and 31.15 mg.g-1, respectively. In addition, the kinetic data of the removal process followed a pseudo-first order (PFO) kinetic model. Negative thermodynamic parameters were indicated that the process is spontaneous and exothermic. Finally, ad(de)sorption experiments' results showed that the synthesized nanocomposite adsorbent has an excellent ability to adsorb cationic dyes after several consecutive cycles.

Decoration of Citrus limon wood carbon with Fe3O4 to enhanced Cd2+ removal: A reclaimable and magnetic nanocomposite.

In the present study, the activated carbon of lemon (ACL) was generated from Citrus limon wood waste and composited with Fe3O4 nanoparticles. The ACL/Fe3O4 magnetic composite was effectively used to eliminate Cd2+ from an aqueous solution. The active surface area values for ACL and ACL/Fe3O4 magnetic composite were 25.99 m2/g and 38.70 m2/g, respectively indicating the effectiveness of Fe3O4 nanoparticles in improving ACL active surface area. The response surface methodology with central composite design (RSM-CCD) was used to determine optimal values of pH, ACL/Fe3O4 dose, contact time, and Cd2+ concentration on the decontamination efficiency. The Langmuir and Freundlich isotherm models had more potential to describe the adsorption process using ACL and ACL/Fe3O4, respectively. The Langmuir-based adsorption capacity was obtained as 28.2 mg/g (ACL) and 39.6 mg/g (ACL/Fe3O4). A pseudo-second order (PSO) model was successfully applied to evaluate the adsorption process kinetic behavior. A higher value of α parameter for ACL/Fe3O4 (5.7 mg/g.min) than that of ACL (3.5 mg/g.min) indicated that the magnetic composite had a greater tendency to absorb Cd2+. In addition, the Weber-Morris model showed that various mechanisms such as intraparticle diffusion and boundary layer effects may have a role in the adsorption process. The study of ad(de)sorption behavior showed that the adsorbents have a good ability to adsorb Cd2+ and no significant change in their performance has been made up to 4 times of reuse. Our results showed that ACL modification using Fe3O4 nanoparticles improved the adsorption efficiency of ACL to remove Cd2+ from the aqueous solutions.

Synthesis of wheat bran sawdust/Fe3O4 composite for the removal of methylene blue and methyl violet.

Magnetically modified nanomaterials have recently gained a great attention in wastewater treatment. In this study, the uptake process of methylene blue (MB) and methyl violet (MV) from aqueous media using wheat bran sawdust/Fe3O4 composite was studied. To specify the surface and structural properties of the wheat bran sawdust/Fe3O4 composite, various analyses such as FTIR, XRD, EDX, Map, TGA/DTG, SEM, VSM, and BET were performed. The results of BET analysis indicated that the specific surface area of the aforementioned composite was 74.25 m2/g, and the average pore size was 65.7A, which indicates that the composite has a mesoporous structure. Also, VSM analysis indicated that the composite has a paramagnetic property with a magnetic saturation of 28.29 emu/g and can be easily eliminated from the aqueous solution by a magnet. Moreover, the highest removal efficiency of MB and MV dyes using the wheat bran/Fe3O4 composite was obtained as 97.46 and 98.75%, respectively, which were significant values. These removal efficiencies were obtained at contact time of 50 min and pH values of 9 and 8 for MB and MV, respectively. Furthermore, the outcomes of equilibrium study showed that the Langmuir model with a correlation coefficient greater than 0.98 describes the equilibrium behavior of the uptake process better than the Freundlich and Dubinin-Radushkevich models. Besides, the maximum sorption capacity of MV and MB dyes using the Langmuir model was obtained as 46.08 and 51.28 mg/g, respectively. Also, the uptake process followed the pseudo-second-order kinetic model, and the thermodynamic study indicated that the uptake process is exothermic and spontaneous.

Adsorption of Crystal Violet Dye Using Activated Carbon of Lemon Wood and Activated Carbon/Fe3O4 Magnetic Nanocomposite from Aqueous Solutions: A Kinetic, Equilibrium and Thermodynamic Study.

Activated carbon prepared from lemon (Citrus limon) wood (ACL) and ACL/Fe3O4 magnetic nanocomposite were effectively used to remove the cationic dye of crystal violet (CV) from aqueous solutions. The results showed that Fe3O4 nanoparticles were successfully placed in the structure of ACL and the produced nanocomposites showed superior magnetic properties. It was found that pH was the most effective parameter in the CV dye adsorption and pH of 9 gave the maximum adsorption efficiency of 93.5% and 98.3% for ACL and ACL/Fe3O4, respectively. The Dubinin-Radushkevich (D-R) and Langmuir models were selected to investigate the CV dye adsorption equilibrium behavior for ACL and ACL/Fe3O4, respectively. A maximum adsorption capacity of 23.6 and 35.3 mg/g was obtained for ACL and ACL/Fe3O4, respectively indicating superior adsorption capacity of Fe3O4 nanoparticles. The kinetic data of the adsorption process followed the pseudo-second order (PSO) kinetic model, indicating that chemical mechanisms may have an effect on the CV dye adsorption. The negative values obtained for Gibb's free energy parameter (-20 < ΔG < 0 kJ/mol) showed that the adsorption process using both types of the adsorbents was physical. Moreover, the CV dye adsorption enthalpy (ΔH) values of -45.4 for ACL and -56.9 kJ/mol for ACL/Fe3O4 were obtained indicating that the adsorption process was exothermic. Overall, ACL and ACL/Fe3O4 magnetic nanocomposites provide a novel and effective type of adsorbents to remove CV dye from the aqueous solutions.

Hydroxyapatite biomaterial production from chicken (femur and beak) and fishbone waste through a chemical less method for Cd2+ removal from shipbuilding wastewater.

Hydroxyapatite (HAp) powder was produced from chicken (femur and beak) and fishbone wastes and used as a green adsorbent to decrease Cd2+ from aqueous media. The HAp powder was generated at 900 °C and characterized using physicochemical techniques. Chicken femur' HAp (16.72 m2/g) had a higher surface compared to chicken beak and fishbone ones. The solution pH was the most important parameter in removing Cd2+. The highest Cd2+ removal was achieved at pH 6, temperature of 25 °C, contact time of 80 min, and adsorbent mass of 2 g/L. The Cd2+ adsorption data fitted well with the quasi-second-order model in kinetics and the Freundlich model in isotherm. The highest adsorption capacity of Cd2+ using HAp-chicken femur, HAp-fish bone, and HAp-chicken beak was determined 22.94 mg/g, 21.54 mg/g, and 21.45 mg/g, respectively. The Cd2+ adsorption using HAp powder was a spontaneous and exothermic process and accidental collisions at the liquid-solid interface were reduced. The decrease of Cd2+ adsorption efficiency was not significant after multiple recovery steps of the desired powders. In addition to Cd2+, other parameters of real wastewater (shipbuilding industry) were reduced by the proposed adsorbents. The utilization of hydroxyapatite powder is expected to be a cheap and eco-friendly method for eliminating metals such as Cd2+.