Curcumin–malic acid based green copolymers for control of scale and microbiological growth applications in industrial cooling water treatment

The formation of calcium sulphate (CaSO4) scale and microbiological growth accumulation poses major problems in cooling water treatment plants, thereby affecting the performance of this type of equipment. In order to inhibit or minimize these problems, new types of green copolymers, poly(curcumin–malic acid) was specially designed and developed from malic acid and curcumin. The structural, chemical and thermal properties of the copolymers were analysed using SEM/EDX, FTIR, UV–Vis, X-ray diffraction, TGA and GPC. The scale inhibition efficiency for CaSO4 scale was investigated by using the static experiment method. The copolymer showed moderate to high sulphate scale inhibition activities based on the amount of curcumin used during copolymerization. The results revealed that due to high molecular weight, the efficiency of the poly(curcumin–malic acid)6 was > 95% at 10 mg/L dosage whereas poly(malic acid) (homopolymer) efficiency was 35.5% at 10 mg/L. Hence, it may be reasonably concluded that poly(curcumin–malic acid)6 is a highly effective CaSO4 scale inhibitor for industrial cooling water treatment applications. In addition, the developed copolymers possess a broad antibacterial activity against Escherichia coli and may be useful as antibacterial agents in the industrial cooling water treatment plants.