Comparison of natural extract as a clean coagulant with alum and natural extract-alum hybrid coagulant for removal of water turbidity.

In this study, the potential of natural coagulants such as plant extracts of Cichorium intybus (Ci), Cichorium pumilum (Cp), and Cichorium endivia (Ce) was investigated for removal of water turbidity. For conducting this study, distilled water and salts of KNO3, NaNO3, NaCl, and KCl were used to prepare the extracts, and parameters such as the turbidity removal percentage, the optimal concentration of plant extracts, the type of extracted extracts, pH, the amount of total dissolved solids, hardness, alkalinity, chloride, and sulfate were examined before and after the coagulation process. In this study, after determining the efficiency of different coagulants in removing tur)bidity from turbid water, the performance of the extracts was compared with the conventional chemical coagulant of aluminum sulfate (alum). The highest turbidity removal efficiency among different extracts was related to the use of Cichorium intybus extract; the high levels of protein and amine in this extract were proved by ninhydrin and Fourier-transform infrared spectroscopy tests. After determining the best plant extract (Cichorium intybus species extract), the hybrid coagulant was prepared using Cichorium intybus plant extract and alum (Ci/alum) in ratios of 1:1, 1:2, and 2:1, and its potential was also studied. The results showed that increasing the coagulant concentration to an optimal level is associated with an enhancement in turbidity removal efficiency. However, increasing the coagulant concentration to levels higher than the optimum value does not affect turbidity removal efficiency, and the removal efficiency remains almost constant. The maximum turbidity removal efficiencies using Ci, alum, and hybrid Ci/alum (1:1 ratio) were 92%, 90%, and 98%, respectively, which indicates the higher efficiency hybrid coagulant in the removal of turbidity from aqueous media. The results also showed that the use of 1 M NaCl solvent for the extraction of coagulants is more effective compared to other solvents used in this study [ABSTRACT FROM AUTHOR]