Synthesis and Characterization of a Coagulating Agent From Plantain Peel Starch (Musa Paradisiaca), As Adjuvant in Water Treatment

Coagulation processes are widely used for water treatment, mainly with chemical coagulants. In this research, starch derived from a residue (plantain peel, Musa paradisiaca) was used as a starting point for a chemical modification. Through acetylation, its chemical structure was modified and characterized by Infrared Spectrophotometry, for its evaluation as a coadjuvant in coagulation operations to reduce the turbidity of raw water. Two experimental designs were developed to evaluate the incidence of modified starch as the main coagulant or in conjunction with a conventional coagulant (Al2(SO4)3), at different Al2(SO4)3 / acetylated starch ratios, in jar-test experiments. In the first experimental design, with the acetylated starch as the main coagulant, turbidity removal percentages reached 47.93% (average value, 41.18%). For the Al2(SO4)3 / acetylated starch coagulation process, 98.91% turbidity removal was reached in the second experimental design (average value, 97.16%). The incidence on turbidity in a jar-test of starch chemical substitution degree and the Al2(SO4)3 / Acetylated starch ratio was investigated using ANOVA analysis. There was a great incidence of the chemical substitution degree and the concentration of acetylated starch used, when modified starch was used as the main coagulant. For the second experimental design, the Al2(SO4)3 / Acetylated starch relationship had a greater incidence on the turbidity removal. Thus, modified starch obtained from plantain peel waste is a promising coadjuvant material for water coagulation processes.