Polymaleic acid was synthesized in water phase by adopting maleic acid as raw material and H ₂O ₂ as initiator. Then a novel polycarboxylate superplasticizer of PMA-AA-AMPS was synthesized by using polymaleic acid (PMA), acrylic acid (AA) and 2-acrylamido-2 methyl-propane sulfonic acid as raw materials, ammonium persulfate as initiator in aqueous media. Additionally, the polymerization conditions were optimized. The results indicate that the copolymer can be prepared under such optimum conditions, i.e., 6∶3∶1.2 molar ratio of MA，AA and AMPS，8% of the mass fraction of ammonium persulfate，6% of the mass fraction of formate sodium, 85 ℃ of the polymerization temperature and 3 h of the reaction time. The characterization results of FTIR indicate that the prepared terpolymer contains functional anionic groups such as carboxyl，hydroxyl，sulphonate and amido groups. The number average molecular weight of the PMAAA from GPC is 5 743 g/mol occupying 81.36% of the whole mass fraction.

The modified lignin-based oil removal flocculant containing the dithiocarbamate group, denoted as MLOF, was prepared by chemical modification of alkali lignin, a byproduct from the pulp and paper industry. Then MLOF was adopted to treat the oily wastewater. And the flocculation conditions were optimized. The results show the removal percentages of oil, COD Cr, suspended solid (SS) and colourity of the effluent can reach to 88.2%, 71.5%, 90.5% and 93.7％ respectively under such conditions as 6.7 of the effluent pH value and 35 mg/L of the flocculant dosage etc. Moreover, the comparison tests with various flocculants indicated that the amount of MLOF was little when treated oily wastewater and the flocculation performance of the modified lignin-based oil removal flocculant apparently prevailed over such high-molecular flocculants as polyacrylamide (PAM), polyaluminium chloride (PAC) and polyferric sulfate (PFS) etc. 