Effect of Poly(Acrylic Acid) Based Polymer Flocculants on Sedimentation of Surface Water

摘要

In most scenarios, there tend to have some impurities such as organic and inorganic substances found on the surface water. These impurities can be classified as insoluble and soluble compounds which in turn, can be purified by filtration and sedimentation prior used. Calcium carbonate (CaCO_3), is one of the most contaminated compounds on surface water, mainly causes severe damage to industrial parts. Therefore, CaCO_3 need immediate removal from raw water before applied to an unit operation by coagulation and flocculation. We mainly focused on precipitation of synthetic water and raw water with polyaluminium chloride (PAC) and synthetic polymer flocculants in this research study. The synthetic flocculants of Polyacrylic acid (PAA), Polyacrylamide (PAM) and Poly(acrylic acid-co-acrylamide) (PAAAM) by free radical polymerization in aqueous. The PAAAM is synthesized in various mole ratio of acrylic acid and acrylamide of 9:1 to 5:5. The polymer flocculants are characterized by FT-IR and ~1H-NMR techniques. The FTIR spectra of the sample showed absorption frequency above 3200-3000, 1750-1550 and 1650-1500 corresponding to OH and CO stretching and NH bending respectively. The ~1H-NMR spectra of PAM showed chemical shift at 1.50, 2.10 and 4.20 ppm regarding to proton of methyl, methylene and amide group respectively and the present of proton resonances at 1.50 and 2.30 ppm regarding to proton of methyl and methylene of PAA. The removal efficiency of suspended CaCO_3 is measured and calculated via turbidity technique. The dosage of PAC 0.1 ppm can remove suspended CaCO_3 approximately 65.33% after the PAAAM with mole ratio of 8:2 is applied to system lead to the removal efficiency increasing to 99.03%.