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.

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.

Layered double hydroxides (LDHs) are emerging catalyst materials with inner layer water molecules and higher anion exchange capacity. They have been extensively used as catalyst materials owing to their high specific surface area, environmental friendliness, lower cost, and non-toxicity. However, the lower surface area and leaching of metal ions from LDHs composites reduce the process efficiency of the catalyst. Modifying the LDHs materials with other materials can improve the surface properties of the composite and enhance the catalytic performance. Herein, this review aims to summarize the recent progress of nanostructured modified LDHs materials, their classification, synthesis, and a detailed discussion on their characterization techniques. Further, this study also discusses the application of nanostructured modified LDHs materials as catalysts in advanced oxidation process (AOPs) for various organic pollutants removal. 

Nanostructured modified layered double hydroxides (LDHs)-based catalysts: A review on synthesis, characterization, and applications in water remediation by advanced oxidation processes

Layered double hydroxides (LDHs) are emerging catalyst materials with inner layer water molecules and higher anion exchange capacity. They have been extensively used as catalyst materials owing to their high specific surface area, environmental friendliness, lower cost, and non-toxicity. However, the lower surface area and leaching of metal ions from LDHs composites reduce the process efficiency of the catalyst. Modifying the LDHs materials with other materials can improve the surface properties of the composite and enhance the catalytic performance. Herein, this review aims to summarize the recent progress of nanostructured modified LDHs materials, their classification, synthesis, and a detailed discussion on their characterization techniques. Further, this study also discusses the application of nanostructured modified LDHs materials as catalysts in advanced oxidation process (AOPs) for various organic pollutants removal.

Abstract Porous PMMA/Na + –montmorillonite (MMT) cation-exchange membranes were successfully prepared by entrapment method in this study. One approach (simple mixing) was to mix commercial PMMA polymer with Na + –MMT clays in solvent for membrane preparation (Membrane A). The other approach (emulsion polymerization) was to synthesize the PMMA/Na + –MMT polymer composite via emulsion polymerization first, followed by membrane casting (Membrane B for Kunipia F clays and Membrane C for PK-802 clays). Membrane morphology and properties were characterized. The thermogravimetric analysis (TGA) verified the near complete incorporation of feed Na + –MMT clays in the PMMA/Na + –MMT composite membranes, while X-ray diffractograms (WXRD) exhibited the slightly enlarged interlayer spacing of Na + –MMT. The range of cation-exchange capacity (CEC) was 9–32 μequiv./47 mm disc. For batch cationic dye adsorption, the best performance was achieved by Membrane B with feed Na + –MMT/MMA (M/P) ratio (w/w) = 0.5 and Membrane C with feed M/P = 0.6, where about 95% Methyl violet adsorption was attained in 2 h. The optimal desorption solution was 1 M KSCN in 80% methanol and its related dye desorption efficiency was 92%. In the flow process using one piece of 47 mm disc of Membrane B (M/P = 0.5), dye solution was recirculated for 6 h and ≥85% dye could be removed. Higher than 94% of dye was desorbed at 1 or 4 mL/min, and the membrane regenerability was proved by successfully performing three consecutive cycles.

(Journal of Membrane Science,326(1):117-129)Preparation of porous PMMA/Na+-montmorillonite cation-exchange membranes for cationic dye adsorption

Investigation on co-combustion of coal gasification fine slag residual carbon and sawdust char blends: Physiochemical properties, combustion characteristic and kinetic behavior

Removal of hazardous crystal violet dye by low-cost P-type zeolite/carbon composite obtained from in situ conversion of coal gasification fine slag

Graded synthesis of highly ordered MCM-41 and carbon/zeolite composite from coal gasification fine residue for crystal violet removal

Effects of acid ionization on the formation mechanism of bimodal mesoporous Al-MCM-41s from coal gasification fine residue and evaluation of adsorption capabilities.

Yu-Hua Wu

Papers

Removal of hazardous crystal violet dye by low-cost P-type zeolite/carbon composite obtained from in situ conversion of coal gasification fine slag

Graded synthesis of highly ordered MCM-41 and carbon/zeolite composite from coal gasification fine residue for crystal violet removal

Effects of acid ionization on the formation mechanism of bimodal mesoporous Al-MCM-41s from coal gasification fine residue and evaluation of adsorption capabilities.