Waste-to-Value-Added Customized Cationic Banana Starch for Potential Flocculant Application

Abstract

Although adding flocculants is an essential step in wastewater treatment and maintaining the stability of the solid-state in solution to produce a loose cell-like structure, in some instances, polymeric material fails to support this due to specific surface charges. Therefore, the current study aimed to develop a cationic form (CBS) obtained from unripe waste bananas as native starch and characterize it as a flocculating agent. The starch from unripe waste banana fruit peel was extracted and synthesized to CBS using an etherification reaction via grafting a cationic moiety such as 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC). In addition, the synthesis process was optimized using quality by design (QBD). The utilization of QBD led to the attainment of the maximum degree of substitution (DS) value of 0.623 under optimal circumstances, which involved reacting moieties such as CHPTAC (0.007 moL) and NaOH (30% w/v) with a reaction duration of 18 h at a temperature of 50 °C. Moreover, elemental, structural, x-ray diffraction, thermal analysis, and surface morphology indicated that a significant cationic fraction was integrated within the BS. In addition, the biocompatibility study showed that both native BS and CBS were > 95% biocompatible against CaCO-2 and HeK-293 cells. Furthermore, the flocculation performance of CBS showed that the transmittance of the supernatant fluid augmented in direct correlation to the sedimentation and flocculation time for CBS. Thus, the modified CBS can be utilized as an economical, safe, and potential substitute against available flocculating agents.

Graphical Abstract