Quaternary ammonium salts for water treatment with balanced rate of sterilization and degradation.

The growing number of infections caused by drug-resistant bacteria which arise from the overuse of antibiotics has severely affected the normal operation of human society. The high antibacterial activity of QAS makes it promising as an alternative to antibiotics, but it suffers from secondary pollution due to its non-degradation. Here we have synthesized a class of gemini quaternary ammonium salts (GQAS) with different carbon chain lengths containing ester groups by using facile methylation reaction. Quaternary ammonium groups contribute to insert negatively charged bacterial membranes, resulting in membrane damage and bacteria death. Compared with conventional single-chain QAS, except for the more efficient antibacterial efficiency attribute to the presence of the second carbon chain, GQAS with alterable antibacterial properties can minimize the possibility of bacterial resistance and reduce the accumulation of GQAS in the environment through the introduction of degradable ester groups. GQAS is completely superior to the commercial bactericide benzalkonium chloride (BAC) in both antibacterial activity and degrade performance, which can be used as a more environmentally friendly bactericide.