Adsorption of Hexavalent Chromium from Wastewater by Using Sweetlime and Lemon Peel Powder by Batch Studies

Abstract

The continuous increase in population and industrialization the degradation of water ecosystem is happened which may be caused due to untreated industrial and municipal wastewater. Hexavalent chromium is one such toxic heavy metal which is considered to be a major pollutant in wastewater. The Cr(VI) adsorptions are checked by varying the parameters like temperature, contact time, pH, and initial adsorbate concentration. It can be concluded that with the increase of agitation speed up to 180 rpm and increase of particle size from 75 to 180, the percentage of adsorption increases with increased uptake and this is due to increased surface area of the adsorbent. As the pH increases, it is observed that a sharp decrease in percentage of adsorption and maximum adsorption capacity is observed at pH 1.25. For the process of removal of toxic heavy metals from aquatic environment, the kinetic models are used. The equilibrium adsorption isotherms are also analyzed by studying Langmuir and Freundlich adsorption isotherms. The pseudo-first- and second-order kinetic models are used for finding best results for experimentation. And pseudo-second-order kinetic model is found to be best-fitted curve for these results. From error analysis and correlation coefficients (R²), the statistical errors such as sum of the square of the error (SSE), sum of the absolute error (SAE), average relative error (ARE) are calculated. The SEM and FTIR analysis are also done to study the physical parameters of adsorbents like morphology and functional group of adsorbents. From the result, it is seen that sweetlime peel powder gives good result for adsorption of removal of Cr(VI) from wastewater as compared to lemon peel powder.