Synthesis Of Activated Clay/starch/fe3o4 Nanocomposite For The Elimination Of Anionic Dye (reactive Red 198) From Aqueous Media

This study examined synthesis of activated clay/starch/fe3o4 nanocomposite for the elimination of anionic dye (reactive red 198) from aqueous media. A method is tested to reduce the pollution of effluents produced in the hide transformation process. Adsorption processes with activated clay, Fe3o4 and starch could constitute a simple, selective and economical alternative to conventional physical-chemical treatments. The adsorption capacity of natural and activated clay, Fe3o4 and starch for anionic dye was RR198. The capacity of starch, fe3o4 and activated clay to adsorb anionic dye (RR198) used in the tannery was much greater. A removal of 90 % was achieved in approximately 10 minutes because of the high affinity between RR198 and activated clay, fe3o4 as well as starch. Activated clay with 0.5 fe3O4 was the most effective adsorbent. 

To this end, the study was subdivided to four segments. The first segment of the study focused on evaluating the efficiency of using magnetite to remove Reactive Red 198 (RR198) dyes from aqueous systems using a batch study. To achieve that, several operational factors like residence time, adsorbent dosage, dye concentration and temperature were appraised. The adsorbent was subjected to different kinds of physicochemical characterization to determine the various characteristics that would assist in the dye uptake process. Characterization results showed that the adsorbent material was highly crystalline with m magnetite, periclase, dolomite, and quartz as some of the crystalline phases. The batch study proved that magnetite is effective in the treatment of dye contaminated water and moreover it performed well in terms of colour taking away, though exceptional results were recorded for RR198 elimination with complete decolourisation occurring in first few minutes of contact. In terms of experimental adsorption capacity, the performance of magnetite was in the order RR198 (12.56 mg/g). 

Mechanisms of adsorption where explained by fitting the experimental data into adsorption isotherms, kinetics, and thermodynamic parameters. Neither, the Langmuir, nor the Freundlich nor the Dubinin Radushkevich, nor the Temkin model could perfectly describe the adsorption of the four dyes onto magnetite, however adsorption kinetics obeyed the pseudo second order model, implying that, the dye elimination process was primarily a chemical process. In accordance with the results of this study, it can be concluded that magnetite can be used effectively for the elimination of RR198 in aqueous solution and thus can be applied to treat wastewater containing dyes.