▎ 摘　　要

NOVELTY - Multiple-effect water-treatment agent comprises 2-10 pts. wt. acrylamide oligomer grafted graphene oxide, 5-40 pts. wt. polyacrylamide, 20-40 pts. wt. poly aluminum silicate iron, 3-25 pts. wt. poly diallyldimethylammonium chloride and 1-5 pts. wt. sodium bicarbonate. USE - The multiple-effect water-treatment agent is useful in water treatment method (claimed). ADVANTAGE - The water-treatment agent is economical. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) preparing water-treatment agent, comprising (i) adding sodium hydroxide and acid into 1-10 mg/ml graphene oxide solution, mixing for 1-10 hours, separating and washing to obtain carboxylated graphene oxide, (ii) mixing graphene oxide and acrylamide oligomer in dimethyl sulfoxide, adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, refluxing at 45 degrees C, separating and washing to obtain acrylamide oligomer grafted graphene oxide, and (iii) uniformly mixing the acrylamide oligomer grafted graphene oxide, polyacrylamide and poly diallyldimethylammonium chloride at more than 45 degrees C, naturally cooling to room temperature, then adding poly aluminum silicate iron and sodium bicarbonate, then mixing uniformly; and (2) water treatment method, comprising (a) passing raw water into a mixing tank, then adding water treatment agent and mixing uniformly, (b) passing the mixed water into a first flocculation tank for preliminary flocculation process, (c) passing the resultant water into a second flocculation tank for secondary flocculation process by adding water-treatment agent again, and (d) filtering water via filtration device.