Hydrophilic substrate for sorbing heavy metals

The method of making a hydrophilic substrate for sorbing by ion exchange heavy metals comprising:

• incorporating in a hydrophilic polymeric substrate a metal chloride selected from the group consisting of zinc chloride, ferric chloride, ferrous chloride, cupric chloride and cuprous chloride;
• said hydrophilic polymeric substrate being formed from a water insoluble hydrophilic polymer selected from the group consisting of cellulose esters, cellulose ethers, starches cross-linked to render them water insoluble, regenerated cellulose, and natural polymers selected from the group consisting of wood pulp, cotton, hemp, jute, sisal, flax, kapok and coconut shell fibers;
• said metal chloride being incorporated in said hydrophilic polymeric substrate by treating said substrate with a solution containing about 20 to about 70% metal chloride;
• and
• then treating said metal chloride incorporated substrate with a sulfide donor selected from the group consisting of hydrogen sulfide, or an aqueous solution of sodium sulfide, potassium sulfide, ammonia sulfide and thioacetamide to convert said metal chloride to a dispersion of a finely precipitated metal sulfide within said substrate;
• said finely precipitated metal sulfide comprising about 5 to about 50% by weight metal sulfide.