Potential of carica papaya seed-derived bio-coagulant to remove turbidity from polluted water assessed through experimental and modeling-based study

Abstract

It is important to develop renewable bio-coagulants to treat turbid water and efficient use of these bio-coagulants requires process optimization to achieve robustness. This study was conducted to optimize the coagulation process using bio-coagulant of deshelled Carica papaya seeds by employing response surface methodology (RSM). This bio-coagulant was extracted by a chemical-free solvent. The experiments were conducted using the Central Composite Design (CCD). Initially, the functional groups and protein content of the bio-coagulant were analyzed. The Fourier Transform Infrared Spectroscopy analysis showed that the bio-coagulant contained OH, C=O and C-O functional groups, which enabled the protein to become polyelectrolyte. The highest efficiency of the bio-coagulant was obtained at dosage of 196 mg/L, pH 4.0 and initial turbidity of 500 NTU. At the optimum conditions, the bio-coagulant achieved 88% turbidity removal with a corresponding 83% coagulation activity. These findings suggested that the deshelled Carica papaya seeds have potential as a promising bio-coagulant in treating the polluted water.