Application of Taguchi design in the removal of heavy metals from Simulated metal solutions using groundnut shell and tea bag as a natural absorbent

Abstract

Abstract Background A series of metal solutions such as chromium sulphate, lead sulphate and nickel sulphate were prepared, and varying concentrations were used to model the optimum conditions that would favour the removal of these metals in polluted situations. Taguchi design was used to set the experiment in motion by using three factors such as pH, concentration and time, although the experiment was done at a fixed temperature of 30 °C as detailed in the study. Result The percentage of heavy metals removal from the solutions at varying conditions was used to model the effectiveness of the adsorbent. All models and their statistical parameters were reported in the study. The model identified as the best was the one involving the removal of chromium concentration using the tea bag adsorbent. The ability of the model to predict other concentrations which were not used in developing the model was high and was reported as preR2 of 0.94. Conclusion The model predicts that the experiment which was conducted at varying pH values ranging from 1.00–8.00 can lead to the effective removal of chromium by decreasing the pH of the system to pH value = 1, and increasing the contact time of the adsorbent tea bag residue. The model confirms the transformation of chromium from hexavalent to trivalent at acidic pH which decreases its ionic solubility in an aqueous system leads to its ultimate removal by the adsorbent