Wastewater treatment using coconut fibre ash as an adsorbent for removal of heavy metals

Abstract

The study aimed at evaluating the performance of coconut fibre ash as an alternative low-cost adsorbent to the synthetic adsorbents used in wastewater treatment. This research aims to identify the optimum condition for the adsorption process, considering the effect of particle size, adsorbent dosage, and contact time of adsorbents of coconut fibre ash in removing lead (Pb), copper (Cu), and zinc (Zn) metal ions from electroplating wastewater. The adsorbents coconut fibre ash was prepared through activation of carbon at 450º C after following proper cleaning and drying process. The experiments were conducted at varying adsorbent dosages (0.2 g, 0.6 g, and 1 g), particle size (50 to 200 microns), and contact times (40 minutes, 80 minutes, and 120 minutes). The result shows that adsorbents show less efficiency in removing Zn metal ions, which is not more than 34% in the case of 1g adsorbent dosage, particle size ranges 100-200 microns, and 120 minute contact time. The maximum removal efficiency of 95.04% and 80% was obtained at the optimum amount (1g) of adsorbent dosage for Pb and Cu respectively. In the case of contact time, it was identified that the optimum condition for maximum removal efficiency is 120 minutes with a 1g adsorbent dosage both for Pb and Cu ions. To ensure maximum removal of metal avoiding any desorption of the metal ion from the adsorbent surface, it was identified that a maximum contact time of 120 minutes should be allowed for adsorption. However, it could be concluded that adsorbents of coconut fibre ash can be used in treating wastewater facilitating good adsorption capacity in removing heavy metals, low cost and availability.