Adsorption of phytohormones from waste coconut water using surface-activated biochar derived from cacao pod husk (Theobroma cacao L.)

Abstract The study investigated the potential of cacao ( Theobroma cacao L.) pod husk as feedstock for the production of activated biochar. The activated cacao pod husk biochar is to be used for the extraction of phytohormones present in coconut water. Cacao pod husk was dried, milled, sieved, and pyrolyzed at 500°C for 1 hour. The resulting raw biochar was then activated using ZnCl 2 . The chemical activation process was optimized by employing Central Composite Design with ZnCl 2 -biochar ratio and holding time as factors. The response was the phytohormone removal/adsorption efficiency from the coconut water. The goal of the optimization was to maximize phytohormone extraction performance. The low and high levels for ZnCl 2 -biochar ratio were 1:1 (w/w) and 5:1 (w/w), respectively. For the holding time, these were set at 30 minutes and 90 minutes, respectively. The optimum chemical activation conditions for phytohormone extraction performance were at 3.1:1 zinc chloride-biochar ratio and 30 minutes holding time. The predicted phytohormone adsorption (extraction efficiency) was 96.0%. Experimental verification of optimum conditions is ongoing. The results demonstrated that surface-activated biochar derived from cacao pod husk is an effective adsorbent for the extraction of phytohormones from waste coconut water. This approach not only helps mitigate the negative environmental impacts associated with waste disposal in the chocolate and coconut oil industries but also provides an opportunity to create value-added products from these resources, contributing to sustainability efforts.