The wastewater generated from textile factories is linked to one of the main water pollution problems; therefore, it is important to reduce the pollutants in industrial effluents before their discharge into environment. The present study was to investigate the appropriateness zeolite-x and kaolin as effective adsorbents for removal of methylene blue from the textile wastewater. Batch adsorption experiments were carried out to assess parameters that influence the adsorption process. The prepared zeolite-x and kaolin were characterized by Fourier Transform Infrared and X-ray diffraction techniques. The results of this study showed that the particle size is 40.77 nm and 0.45 nm kaolin and zeolite-x respectively. The performance of zeolite-x adsorbent is best at the optimum pH 4 with removal efficiency of 97.77% and kaolin adsorbent at pH 6 with removal efficiency of 86.86%. The optimum contact time was obtained at 60 and 80 minutes for zeolite-x and kaolin respectively. While optimum adsorbent dosage was obtained at 0.4 and 0.6 grams with removal efficiency of 97.12% and 87.75% for the zeolite-x and kaolin adsorption experiment respectively. The confirmed square sum errors values are 1.0×10 -4 and 1.0×10 -3 for zeolite-x and kaolin, respectively. The Adsorption isotherms results have well fitted to Freundlich isotherm than Langmuir isotherm. The adsorption kinetics results were best fitted the pseudo second order model. The result shows that the zeolite-x has high removal efficiency than kaolin at the same operating conditions. Application of this method can be economically, environmentally, and socially feasible to address wastewater problems. Further research has to be carried out on the removal capacity of this adsorbent for organic dyes not only from the textile industry but also from leather industries and soap industries.

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In the current study, the potential sorption of Cr (VI) ions through a zero-valent silver nanoparticle synthesized by a green approach has been studied. The objective of this research was to remove Cr (VI) from aqueous solution using zero-valent silver nanoparticles synthesized from Moringa stenopetala leaves extract. The synthesized silver nanoparticles were characterized using X-ray diffractometer and UV-visible spectrophotometer. The grain size of nanoparticles was found to be 19.5 nm confirming the crystalline structure of the mesosphere and showed the maximum absorption at 419 nm. In order to determine parameters that influence the adsorption mechanism, batch adsorption experiments have been conducted. Results obtained for removal of Cr (VI) ions showed that efficiency of removal improved as adsorbent dosage increased until the equilibrium point reached at 50 minutes. However, as the pH of the solution increased from 1 to 8, and as the Preliminary concentration of Cr increased, removal efficiency decreased. Adsorption isotherms were investigated by applying the models of Langmuir and Freundlich. The Freundlich isotherm can better explain the removal of Cr (VI) ions, offering correlation coefficient values greater than the Langmuir isotherm model. Adsorption kinetics regression results studied by the pseudo-first and second-order models moreover proved that a pseudo-first-order was further accurately represented by the adsorption kinetics. In order to alleviate wastewater problems, the implementation of this approach is able to cost-effective, eco-friendly and publicly viable. To improve its removal effectiveness and compare it with other adsorbents, additional study on surface modification of this adsorbent is required.

The current boom in the industrial sector of the country is arise scientific concern about environmental contamination by heavy metals such as chromium. The objective of this project is to fabricate a sensitive and selective electrode for differential pulse voltammetric determination of Cr (VI) in water samples and demonstrate its applicability in complex matrices such as tannery effluent. The drop casting method is use for electrode development. Experimental variables that can influence the DPV response of the developed electrode for Cr (VI) including strength of supporting electrolytes, pH of the solution, and concentration parameters were optimized. The figures of merit of the developed electrode were evaluated and the applicability was demonstrated through determination of Cr (VI) in tannery effluent water. The developed electrode was detected a very low level of Cr (VI) in acetate buffer at pH 5 with limit of detection and limit of quantification 0.0885 and 0.2950 μmol L −1 , respectively. The linear calibration plot is R 2 value of 0.999 suggesting a very good correlation between DPV current response and concentration of Cr (VI). The current electrode was simple to develop and can successfully be applied for the determination of Cr (VI) in wastewater samples.