The Potential of Cacao Pod Rind Waste (Theobroma cacao) to Adsorb Heavy Metal (Pb and Cd) in Water

Abstract

Jember, Indonesia, is one of the districts producing large amounts of cocoa (Theobroma cacao) in Indonesia. The main waste of cocoa production is the cacao pod rinds, comprising approximately 75% of the raw product. Cacao pod rind waste, containing ~12.67% pectin, has the potential to adsorb heavy metals. The objective of this study is to analyse the potential benefits of cacao pod rind waste from Jember cacao plantations to adsorb heavy metals such as Pb and Cd in water. This study represents true experimental research using the completely randomized design (CRD) method. There were control group (C) and three treatment groups (T1, T2 and T3 with 100 g/L, 300 g/L and 600 g/L, respectively) with six repetitions. Both parameters (Pb and Cd) were analysed in 24 samples using atomic adsorption spectrophotometry (AAS). The results show that as more cacao pod rind waste is exposed, the volume of water becomes increasingly turbid. Welch’s F test showed that there were significant differences in the levels of Pb in the control group (F, 7.125; Sig, 0.002) and three treatment groups (Sig, 0.00; 0.003; 0.002). In regard to Cd, the one-way ANOVA test using LSD post hoc showed that there were significant differences between the control and treatment groups (F, 3.142; Sig, 0.048; Sig 0.048, 0.009, 0.04). Thus, cacao pod rind waste from Jember has the potential to adsorb heavy metals such as Pb and Cd in water. It could contain heavy metal pollution and maintain sustainability of the environment.