Optimization of Hazardous Malachite Green Dye Removal Process Using Double Derivatized Guar Gum Polymer: A Fractional Factorial L9 Approach

According to the research, zeolitic imidazolate framework (ZIF‐67) and graphene oxide (GO) nanosheets were synthesized with a guar gum (GG) biopolymer substrate to form two‐component hybrid biocomposites: GO/ZIF‐67 (GOZ), GG/ZIF‐67 (GZ), and three‐component hybrid with GO/GG/ZIF‐67 (GGZ) substrate polymer. These composites were used to adsorb malachite green (MG) cationic dye from an aqueous solution at room temperature. The chemical fractions, morphological and structural properties of the hybrid biocomposites were determined using a Fourier transform infrared spectrometer (FTIR), scanning electron microscope (SEM), X‐ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) analyses. The adsorption of MG dye was carried out on the two‐component and three‐component hybrid biocomposites with a polymer substrate under different experimental conditions. The high surface area of GZ, GOZ, and GGZ was 1362.89, 754.89, and 833.67 m 2 g −1 , respectively, and the total pore volume was 0.90 cm 3 g −1 for GZ, and 0.51 cm 3 g −1 for GOZ and GGZ, respectively. The removal of MG pollutant follows the pseudo‐second order model and the Langmuir model. The adsorption mechanism involves hydrogen bonding, π‐π stacking, and electrostatic interactions. The GOZ, GZ, and GGZ hybrid biocomposites showed the maximum removal efficiency at 66.6%, 74.4%, and 90.1%, respectively. The data show that the removal of MG after 3 cycles was 90%, 86%, and 82%.

Peat of Brunei Darussalam shows a great potential for the removal of methylene blue (MB) and malachite green (MG) dyes from aqueous solution. Carefully controlled batch experiments performed by changing one parameter at a time indicate that the optimum time periods of agitation and settling required for maximum removal of MB are 2.0 and 1.0 h, respectively, while these values for MG are 4.0 and 1.0 h, respectively. The optimum pH is determined to be the ambient value, and under the optimum conditions, 90 % removal of both dyes was determined under laboratory conditions. The equilibrium adsorption data analyzed for various isotherm models suggest that the Sips and Redlich–Peterson (R–P) models are valid for MB and MG, respectively. Further, thermodynamic studies show that the adsorption of both dyes on peat is spontaneous and endothermic. The adsorption capacities (q max) of MB and MG dyes on peat are 0.45 and 0.31 mmol g−1, respectively. Characterization of the surfaces of peat before and after treatment of dyes by SEM and FTIR provides conclusive evidence of adsorption of both dyes. Kinetics studies indicate that the adsorption of both MB and MG dyes is favored toward the pseudo-second-order model, with a little contribution of MG to the pseudo-first-order model. These results suggest that peat is a potential low-cost adsorbent for the removal of MB and MG dyes.

In this study, the adsorption potential of Teak (Tectona grandis) leaf powder (TLP) to remove Methylene blue (MB) and Malachite Green (MG) dye molecules from aqueous solution was investigated. Batch experiments were conducted to evaluate the influence of operational parameters such as, pH (2-9), adsorbent dosage (1-7 g/L), contact time (15-150 minutes) and initial dye concentration (20-120 mg/L) at stirring speed of 150 rpm, on the adsorption of MB and MG on TLP. The maximum removal efficiency of 98.4% and 95.1% was achieved for MB and MG dye, respectively. The experimental equilibrium data were analyzed using Langmuir, Freundlich and Temkin isotherms and it was found that it fitted well to the Freundlich Isotherm model. The surface structure and morphology of the adsorbent was characterized using Scanning electron microscopy (SEM) and the presence of functional groups and its interaction with the dye molecules were analyzed using Fourier transform infrared (FTIR). Based on the investigation, it has been demonstrated that the teak leaf powder has good potential for effective adsorption of Methylene blue and Malachite green dye.

A study on the synthesis of magnetized adsorbents from coal fly ash (FA) for the adsorption of malachite green (MG) dye has been conducted. The method involves acid activation and ferrite magnetization of FA. The activation of FA was performed by mixing it in an HCl solution, while the magnetization was carried out by the coprecipitation method using the molar ratio of 1:2 of Fe2+/Fe3+. The magnetized coal fly ash adsorbent (FA/Fe3O4) was then utilized to adsorb the MG dye, and the results were compared with that adsorbed by activated fly ash (AFA). Characterization of the materials was carried out using Atomic Absorption Spectroscopy (AAS), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), and Vibrating Sample Magnetometer (VSM). The optimized parameters in the adsorption study were pH, adsorbent mass, contact time, and initial concentration. The optimum conditions for the adsorption of MG dye with AFA and FA/Fe3O4 are obtained at pH 7, the adsorbent mass of 0.1 and 0.25 g respectively, a contact time of 45 minutes, and the initial concentration of MG dye of 175 ppm. The MG adsorption on both adsorbents follows a pseudo-second-order kinetic model and can be best described by the Langmuir isotherm adsorption model. The synthesized adsorbent is prospective as it is low cost and easily separable from the solution using an external magnet after adsorption. Keywords: Adsorption, coal fly ash, magnetite, malachite green

Assembly, characterization, and adsorptive-removal efficiency of Cu-doped-ZIF-8 adsorbents

BACKGROUNDThe present study focus on the development and feasibility of a blue light emitting diodes (LEDs) source based slurry type spiral‐shaped photocatalytic reactor for degradation of malachite green (MG) dye using P25 Degussa TiO2. The influence of operational parameters such as amount of catalyst loading, initial concentration of dye, and pH of the medium has been studied for optimization of MG dye degradation.RESULTSThe photocatalytic degradation of malachite green dye under separate irradiation by blue and by ultraviolet LED was nearly the same (∼76%). The photocatalytic activity using blue LED irradiation was observed due to the synergistic effect of MG dye adsorption on P25 Degussa, which extends the spectral response of TiO2 to the visible region (449 nm). The optimized degradation of 20 mg L‐1 dye was observed at pH 8 using 0.5 g L‐1 of catalyst under irradiation by ultraviolet and blue LEDs for 1 h and 3 h, respectively.CONCLUSIONIt was found that the synergistic effect of adsorption of malachite green dye on TiO2 surface helped to enhance photocatalytic degradation under blue LED irradiation. The application of a blue LED for photocatalytic degradation of malachite green dye is economical and feasible compared with use of an ultraviolet LED. © 2014 Society of Chemical Industry

The prospective of maize cob powder (MCP) as an effective adsorbent for the removal of malachite green (MG) and congo red (CR) dyes from aqueous solution was investigated. The presence of functional groups and pores on maize cob powder were confirmed by FTIR and SEM analysis. Batch adsorption studies were conducted and various parameters such as contact time, adsorbent dosage, initial dye concentration, pH and temperature were examined to observe their effects in the dyes adsorption process. The optimum conditions for the adsorption of MG and CR onto the adsorbent (MCP) was found to be: contact time (60mins), pH (10.0) and temperature (303 K), adsorbent dose (1 g) for an initial MG dye concentration of 50 mg/L and contact time (80mins), pH (2.0) and temperature (343 K) for an initial CR dye concentration of 50 mg/L and adsorbent dose 1.0 g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich isotherm model for CR dye adsorption and Langmuir Isotherm for MG adsorption. The maximum adsorption capacity was found to be 13.02 mg/g and 9.41 mg/g for the adsorption of MG and CR dyes respectively. The kinetic data conformed to the pseudo-second-order kinetic model. Thermodynamic quantities such as Gibbs free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were evaluated and the negative values of ΔG0, ΔH0 and ΔS0 obtained indicated the spontaneous and exothermic nature of the MG adsorption process while positive enthalpy (ΔH0) indicated an endothermic nature of CR adsorption process.

Polyurethane foam was chemically functionalized with salicylate through the –N˭N– group generating a stable chelating sorbent PUFSalicylate (PUFS) for being used as a low cost, available, and renewable adsorbent for the removal of Malachite Green (MG) textile dye from aqueous solutions. Batch experiments were carried out for sorption kinetics and isotherms. The synthesized adsorbent was characterized by Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microcopy (SEM), and X-ray diffraction. The present study is related to the removal of colorants. Adsorption of MG dye on PUFS was studied as a function of different experimental parameters such as temperature, contact time, amount of adsorbent, and pH. A spectrophotometer technique was used for measuring the extent of adsorption. The data were fitted with Langmuir and Freundlich isotherm equations and their corresponding constants were calculated from the slopes and intercepts of their respective lines. From the measured adsorption isotherms at different temperatures 298, 308, and 318 K, it was found that adsorption increases as the temperature increases within this range. The measured adsorption amount of MG dye increases with increased pH.

Applications of functionalized porous carbon from bio-waste of Alnus nepalensis in energy storage devices and industrial wastewater treatment

Toward better monitoring of human noroviruses and F-specific RNA bacteriophages in aquatic environments using bivalve mollusks and passive samplers: A case study.

Natural bentonite was functionalised by methanol to obtain a novel methoxy bentonite structure (MXBE) of enhanced adsorption capacity for malachite green dye (MG.D). The adsorption properties of MXBE adsorbent were illustrated based on the classic equilibrium studies and the advanced equilibrium modelling according to the statistical physics theory. The uptake of MG.D by MXBE follows the kinetic properties of the Pseudo-First order model (R2 > 0.9) and exhibits the equilibrium behaviour of a classic Langmuir isotherm (R2 > 0.9). This demonstrates the physical adsorption of MG.D in homogeneous and monolayer form considering the Gaussian energy value (4.24–6.53 kJ/mol). The description of the adsorption system according to the statistical physics theory and the assumption of the Monolayer model with one energy site was accomplished considering the steric and energetic parameters. The saturation adsorption capacity of MXBE during the uptake of MG.D is 435.12 mg/g (313.13 K) and this value depends on the saturation of the structure with numerous active adsorption sites (Nm = 121 to 240.6 mg/g) and the efficiency of each active site to adsorb up to three MG.D molecules (n = 1.92 to 2.68). Considering the adsorption energy (ΔE = 16.02 to 17.94 kJ/mol), the uptake of MG.D occurred by physical mechanisms involving mainly hydrogen bonding and dipole bonding forces. The recognised thermodynamic functions (entropy, internal energy, free enthalpy) validate the spontaneous and endothermic behaviours of the MG.D adsorption reactions by MXBE.

The present world is confronted with perils of freshwater resources and hence contamination of water bodies in specific has raised genuine concerns. The possible application of biopolymers and its composites for removal of hazardous dyes has been widely investigated in recent studies. Polymers derived from biological sources, such as polysaccharides, lignin, alginate, and bacterial polymers, are the major polymeric materials adopted for water purification systems. Driven by the potential applications of such biopolymers for wastewater remediation, researchers take a great deal of interest in developing biomaterials that can perform specific functions in response to a given set of environmental conditions and parameters. One way to design such materials is to create composite functional structures, which can adsorb or bind with a specific type of contaminant present in water bodies. Composites are highly advantageous for adsorption applications as they possess desired properties of both parent materials and hence limitations of individual components can be overcome. In this vein, nano-sized bio-composites can present superior adsorption capacities in comparison with their micro-sized counterparts. This chapter focuses on the principles of designing and preparation of bio nanocomposites particularly from polysaccharides, which offer advanced applications in highly functionalized and molecule specific adsorption and super adsorption of hazardous dyes. Such emerging technologies and recent advancements in the application of polysaccharides as composite nanostructures, for water purification, have been thoroughly discussed. Along with recent advancements, the chapter also outlines the developmental history, current status, future prospects, and significance of exploring and utilizing biopolymer nanocomposites in this domain.KeywordsAdsorptionBiopolymersBiosorptionCelluloseChitinChitosanHazardous dyesNanocompositePolysaccharidesStarchWastewater treatment

Radiation-induced cytogenetic and hematologic effects on aquatic biota within the Chernobyl exclusion zone

Seeking to increase agricultural production and, at the same time, concern for the environment, this work seeks to use the MOHID Land platform coupled with the SWAT model to demonstrate the feasibility of applying such software to study the transport of contaminants in water environments. To this end, a simulation of a corn plantation was developed at the Panorama site, in the municipality of Varre-Sai, Rio de Janeiro. It was concluded that the MOHID Land platform can be used to study the transport of contaminants in water bodies, being a management tool and decision-making aid for engineers and public entities seeking to adopt measures to control pollution in the environment.

Nature of the shift in the absorption band of the molecular forms of azo dyes adsorbed onto the surface of aluminosilicate catalysts