Researchers at the State Key Laboratory for Oxo Synthesis and Selective Oxidation of the Lanzhou Institute of Chemical Physics of the CAS have received a national invention patent for the preparation method of a high polymer material chemical sand-fixing agent on May 18.

The procedure of preparation comprises the following steps: extracting lignin from the alkaline pulping and papermaking waste liquor by acidulation, using formaldehyde and sodium sulfite or sodium bisulfite to perform sulfomethylation modification to lignin, then adopting acrylic acid to perform graft copolymerization modification to sulfomethylated lignin, and obtaining the new high polymer material chemical sand-fixing agent.

The method could solve the pollution problem of the paper-making effluent to the environment, and its cost is low. The facilely synthesized sand-fixing agent is water-soluble and degradable, and could keep water and moisture, and is helpful for plant growth.

In their previous work, researchers have received a national invention patent for the preparation method of a lignosulfonate graft copolymer chemical sand fixing agent. In the method, neutral paper-making waste liquid is evaporated and condensed; lignosulfonate in the neutral paper-making waste liquid is extracted; an aldehyde compound and an unsaturated acylamide, unsaturated acid or unsaturated ester compound are respectively or simultaneously used as reaction compositions; and the lignosulfonate is subjected to chemical modification to synthesize a series of lignosulfonate graft copolymer chemical sand fixing agent.

Paper-making black liquor is the black liquor left after the separation and extraction of lignin used for making paper from plants. The synthesis of chemical sand-fixing agents using lignin or lignosulfonate extracted from paper-making black liquor can not only reduce the pollution of paper-making waste to environment, but also convert waste into useful resources and provide a cheap sand-fixing material for windbreak and sand-fixation.