Coagulation activity of liquid extraction of Leucaena leucocephala and Sesbania grandiflora on the removal of turbidity

Turbidity is removed by adding a chemical coagulant, which produces a secondary toxic of alumina residues in the water. Therefore, the aim of study was to evaluate the coagulation activity of NaCl extract from Leucaena leucocephala and Sesbania grandiflora seeds on the removal of turbidity for water purification. The proximate composition of the seeds was determined. Fourier transform infrared spectroscopy was used to identify the functional groups of protein, and the surface morphology was observed by SEM-EDS. To obtain the optimized condition, all experiments were evaluated by artificial turbid water before being applied on the natural water (i.e., Selokan Mataram). The coagulation process was evaluated by concentration (M), dosage (mL/L), and pH in terms of turbidity, total dissolved solids, and transmittance of light. The results showed that both coagulant seeds contained 25.32 and 30.81% of protein. These coagulants could remove the turbidity by 99.7% for L. leucocephala and 94.24% for S. grandiflora from artificial turbid water at the optimized concentration of 1.0 M, and dosage of 5 and 10 mL/L, respectively. At pH 5 the removal of turbidity from Selokan Mataram was 99.4% for L. leucocephala and 97.23% for S. grandiflora.