METHOD OF TREATING LIGNIN-CONTAINING PULP AND PAPER INDUSTRY EFFLUENT WATER WITH CHITOZAN SOLUTIONS Russian patent published in 2009 - IPC C02F1/58 C02F103/28 

FIELD: treatment facilities.

SUBSTANCE: invention relates to the methods of removing technical lignins such as lignosulphonates from effluent water and can be used in pulp production. Method of treating lignin-containing pulp and paper industry effluent water containing lignosulphonates, reducing substances (RS) - polysaccharides and other pulp production components implies their precipitation as compounds with natural aminopolysaccharide - chitosan. Chitosan with molecular weight of 300-500 kDa is used in the invention. The weight relation chitosan:lignosulphonate amounts to 0.2-0.3:1 and the precipitation temperature is equal to 22-90°C.

EFFECT: method provides for 80-99% extraction of lignosulphonates and 60% extraction of reducing substances with the initial concentration of the lignosulphonates in the solution being equal to 2,5-100 g/L, pH=1-6, RS=4,25%.

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