Removal of chromium in aqueous solutions using powdered activated carbon treated with humic acid

A dissertation submitted to the Department of Civil Engineering for the MSc in Environmental ManagementBecause of its toxicity, Chromium (VI) causes water pollution and threatens to the environment. Its solubility in nature is strongly inf1uenced by adsorption process. Relatively few studies have focused on adsorption properties onto the Powdered Activated Carbon (PAC). In this work. the PAC and humic acid treated PAC adsorption properties were compared.This study proposed humic acid treated Powdered Activated Carbon as a low cost adsorbent for removal of Chromium from aqueous solution. Adsorption of Cr (VI) by PAC was conducted using batch tests. The int1uence of pH, contact time, initial Chromium concentration on removal of Chromium (VI) was investigated. This test was also repeated with humic acid treated PAC. The optimum initial pH for maximum adsorption of Cr (VI) from aqueous solution was found to be 4.0. The removal efficiency was found to be correlated with the initial Cr (VI) concentration, ionic strength, as well as the contact time between the Chromium (VI) and the adsorbent. For humic acids treated PAC, the optimum adsorption also was found at 4.0. Therefore acidic medium is favorable to the Chromium removal.According to the experimental data obtained from this study, the percentage metal removal increased with increasing PAC dosage at the same initial metal concentration. After using humic acid treated PAC increased the metal removal percentage with same adsorbent dosage.When the effluent is in acidic medium, the PAC is more suitable as the adsorbent while the humic acid treated PAC is more suitable for basic effluent