Removal of Chromium (VI) from Tannery Effluent Using Bio-Char of Phoenix reclinata Seeds

The potential of the Senegal date palm (Phoenix reclinata) seed bio-char to remove chromium (VI) ions from aqueous solutions by\r\nadsorption was investigated. Adsorption experiments were performed on the\r\ntannery effluent and standard aqueous solutions of chromium (VI) for varying\r\nadsorbent doses, contact times, pH, temperatures, and interfering anionic ions\r\nby batch mode. Phoenix reclinata seeds (PRS) bio-char was used in the investigation and the residual\r\nchromium (VI) was determined using the atomic absorption spectrophotometer\r\n(AAS). Results showed that the bio-char removed up to 86% of chromium (VI) ions\r\nin the effluent at pH 2. The highest percentage adsorption registered was 97%\r\nin an aqueous solution of chromium (VI) at pH 1 and this dropped to less than\r\n10% at pH greater than 2. A general increase in adsorption with the increase in temperature was\r\nobserved but reduced when the temperature was raised beyond 60°C. The presence of interfering anions caused a reduction in the\r\nadsorption of chromium (VI) ions. The adsorption process fitted both Langmuir\r\nand Freundlich adsorption models and the maximum adsorption capacity, Qo, was 0.6593 mg/g. Thus, PRS bio-char can therefore be used by industries and institutions like secondary schools to treat\r\neffluents that contain chromium (VI).