Adsorptive performance of MOF nanocomposite for methylene blue and malachite green dyes: Kinetics, isotherm and mechanism.

Application of adsorption process for effective removal of emerging contaminants from water and wastewater.

The current study focused on the use of gum Arabic grafted polyacrylamide (GA-cl-PAM) hydrogel as a self-template for the in situ synthesize of zinc oxide nanoparticles (ZnO NPs) and the application of synthesized nanocomposite as a potential adsorbent to remove synthetic dyes especially malachite green (MG) from aqueous solution. Different characterization techniques supported in situ synthesis of ZnO NPs onto polymer matrix. The gum Arabic-crosslinked-poly(acrylamide)/zinc oxide nanocomposites (i.e., GA-cl-PAM/ZnO nanocomposite) exhibited much better surface properties as compared to the parental hydrogel matrix. The swelling abilities of the GA-cl-PAM/ZnO nanocomposites with different concentrations of acrylamide were also checked and the nanocomposite with 7.03 × 10–4 mol/L of acrylamide exhibited maximum swelling capacity of 2354%. The nanocomposite adsorbed approximately 99% MG dye with 0.4 g/L adsorbent dose at neutral pH. Adsorption kinetics and isotherm followed pseudo-second-order and Langmuir isotherm models, respectively with the high adsorption capacity of 766.52 mgd/gads at 25 °C. It was observed that the dye molecules were adsorbed onto GA-cl-PAM/ZnO nanocomposite mostly via electrostatic interactions, hydrogen-bonding and pore-diffusion mechanisms. Diffusion of dye molecules within the internal structure of GA-cl-PAM/ZnO nanocomposite followed the combination of both liquid film as well as intraparticle diffusion mechanisms. Furthermore, nanocomposite was applied ten times consecutively to adsorb MG dye from aqueous solution. Therefore, GA-cl-PAM hydrogel have capability to be used for the in situ ZnO NPs synthesis and thus synthesized nanocomposite can be used effectively to treat dyes polluted wastewater.

In-Situ Synthesis of ZnO Nanoparticles using Gum Arabic Based Hydrogels as a Self-template for Effective Malachite Green Dye Adsorption

Removal of pharmaceutical pollutants from synthetic wastewater using chemically modified biomass of green alga Scenedesmus obliquus.

Heavy metals contamination has become a global environmental problem owing to anthropogenic sources. They are considered a stern threat to humans, aquatic life, and harmful pollutants to water resources due to their toxicity and carcinogenicity. Nanomaterials (NMs) have been used extensively from the available diversity of sorbents for heavy metals removal from wastewater. This review looks at the results of research undertaken using various NMs in the sequestration of Cr (VI). NMs have shown to be efficient and effective for the treatment of wastewater polluted by Cr (VI) owing to their unique properties like surface effect and quantum effect. Besides their large surface area, they also show exclusive characteristics like higher capacity, higher specificity, higher affinity, self-assembly, great reactivity, and catalytic-potential, making them superior adsorbing materials than traditional materials for Cr (VI) removal. The functionalization of these NMs was discovered to enhance their characteristics, hence improving the sorption capacity of NMs for Cr (VI) sorption. From previous studies reported, synthesized NMs had high sorption capacity for Cr (VI) and high retention of the sorbate metals. The Cr (VI) sorption onto various NMs or its functionalized materials were observed to depend on the pH, quantity of sorbent, contact time and temperature. The Langmuir isotherm and pseudo-second-order kinetic models best depicted the equilibrium data of the sorption processes. The determined sorption capacity of the various NMs for Cr (VI) sorption determined from the Langmuir model ranged from 3.197 to 666.67 mg/g for carbon nanomaterials, 8.67–1052.63 mg/g for metal and metals oxide NMs and 59.17–854.7 mg/g for polymers composite.

A review of hexavalent chromium removal from aqueous solutions by sorption technique using nanomaterials

A study on Effects of pH, Adsorbent Dosage, Time, Initial Concentration and Adsorption Isotherm Study for the Removal of Hexavalent Chromium (Cr (VI)) from Wastewater by Magnetite Nanoparticles

P.V. Haseena

Papers

A study on Effects of pH, Adsorbent Dosage, Time, Initial Concentration and Adsorption Isotherm Study for the Removal of Hexavalent Chromium (Cr (VI)) from Wastewater by Magnetite Nanoparticles

Adsorption of Ammonium Nitrogen from Aqueous Systems Using Chitosan-Bentonite Film Composite