clay and malachite-green

A facile, ecofriendly, and cost-effective method was developed to prepare a microporous material based on natural chemically modified bentonite with silver ions (BN-Ag

Topics: Anti-Bacterial Agents; Bentonite; Clay; Escherichia coli; Metal Nanoparticles; Microbial Sensitivity Tests; Ozone; Rosaniline Dyes; Sewage; Silver; Spectroscopy, Fourier Transform Infrared; X-Ray Diffraction

The simultaneous reduction of Chromium(VI) (Cr(VI)) and oxidation of cationic dyes in dispersions of Montmorillonite K10 (MK10) were examined under visible irradiation (λ>420 nm). The iron species (i.e. iron oxides, structural iron and exchangeable interlayer iron) in layered clays are active for catalytically reducing Cr(VI) by using Malachite green (MG) and Rhodamine B (RhB) as the electron donors. Molecular oxygen does not have a significant effect on clay-catalyzed Cr(VI) reduction, but is important for oxidative degradation of dye pollutants. MK10 catalysts are stable and reusable, and are therefore considered as a promising naturally-abundant material for decontamination of dye and heavy metals.

Topics: Aluminum Silicates; Bentonite; Catalysis; Chromium; Clay; Coloring Agents; Electrons; Iron; Models, Chemical; Oxidation-Reduction; Rhodamines; Rosaniline Dyes

We report a method for the removal of malachite green (MG) by adsorption and precipitation using nano-sized aminopropyl functionalized magnesium phyllosilicate (AMP) clay. MG, which is used in aquaculture and fisheries, is a carcinogenic and mutagenic compound. In response to these health risks, many efforts have been focused on adsorption of MG onto various adsorbents, which is a versatile and widely used technique for removing MG from water. Herein, we describe the adsorption and precipitation of MG using AMP clay, as well as the alkaline fading phenomenon of MG. In this study, prepared AMP clay and the precipitate product after the reaction of MG-AMP clay mixture were characterized. In addition, adsorption isotherms and kinetics, as well as thermodynamic studies are presented. Based on the results, we suggest a macro- and microscopic removal mechanism for the adsorption and precipitation of MG using AMP clay. An AMP clay dosage of 0.1 mg mL(-1) exhibited a maximum removal capacity of 334.80 mg g(-1) and 81.72% MG removal efficiency. With further increases of the AMP clay dosage, removal capacity by AMP clay gradually decreased; at dosage above 0.2 mg mL(-1) of AMP clay, the removal efficiency reached 100%.

Topics: Adsorption; Aluminum Silicates; Clay; Magnesium; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Reference Standards; Rosaniline Dyes; Silicates; Thermodynamics; X-Ray Diffraction

Synthesis of nanoclay nanocomposite has been undertaken by using polyacryalic acid (PAA) in aqueous medium and ultrasound environment and its application in dye removal has been investigated. The synthesized product was characterized by using FTIR and XRD techniques. The sonosorption capacity of the product namely PAA-nanoclay composite was determined by choosing malachite green (MG) dye as a model pollutant. The effects of various parameters such as nanocomposite loading, pH, various process conditions etc. have been studied. On comparing the results obtained with that of nanoclay as an adsorbent, it was found for an initial concentration of 500mg/l, the PAA-nanoclay nanocomposite exhibited higher percentage of pollutant removal (68%) and for nanoclay it was 54%. The adsorption data has been correlated using Langmuir and Freundlich models. The fit of the Freundlich isotherm model was found to be good in the entire range of concentration for the experimental sorption data obtained on the nanoclay nanocomposite. A plausible reaction mechanism for use of PAA-nanoclay nanocomposite as an adsorbent is also proposed.

Topics: Acrylic Resins; Adsorption; Aluminum Silicates; Clay; Coloring Agents; Hydrogen-Ion Concentration; Nanostructures; Rosaniline Dyes; Surface Properties; Time Factors; Ultrasonics; Water

The ability of bentonite to remove malachite green from aqueous solutions has been studied for different adsorbate concentrations by varying the amount of adsorbent, temperature, pH and shaking time. Maximum adsorption of the dye, i.e. >90% has been achieved in aqueous solutions using 0.05 g of bentonite at a pH of 9. Thermodynamic parameters such as DeltaH degrees, DeltaS degrees and DeltaG degrees were calculated from the slope and intercept of the linear plots of lnK(D) against 1/T. Analysis of adsorption results obtained at 298, 308, 318 and 328 K showed that the adsorption pattern on bentonite seems to follow the Langmuir, Freundlih and D-R isotherms. The temperature increase reduces adsorption capacity by bentonite, due to the enhancement of the desorption step in the mechanism. The numerical values of sorption free energy (E(a)) of 1.00-1.12 kJ mol(-1) indicated physical adsorption. The kinetic data indicated an intraparticle diffusion process with sorption being first order. The rate constant k was 0.526 min(-1). The concentration of malachite green oxalate was measured before and after adsorption by using UV-Vis spectrophotometer.

Topics: Adsorption; Aluminum Silicates; Bentonite; Cations; Clay; Coloring Agents; Hydrogen-Ion Concentration; Kinetics; Models, Chemical; Rosaniline Dyes; Solutions; Thermodynamics; Waste Management; Water Pollutants, Chemical

Photostable formulations of the herbicide bensulfuron-methyl [BSM, 2-(4,6-dimethoxypyrimidin-2-carbamoylsulfamoyl)-o-toluic acid methyl ester] were achieved by adsorbing it on clays or on clays pre-adsorbed with the organic cation malachite green (MG). Fourier-transform infra-red (FTIR) spectra showed the existence of strong interactions between the pre-adsorbed MG and the herbicide. The photostabilization of BSM obtained with clay-MG was mainly due to pacification of clay surface by MG and a deactivation mechanism via energy transfer between the two organic molecules adsorbed on the surface of the clay.

Topics: Adsorption; Aluminum Silicates; Clay; Kinetics; Light; Rosaniline Dyes; Spectroscopy, Fourier Transform Infrared; Sulfonylurea Compounds