Aluminum and Iron(III) Chemistry
Jean-Yves Bottero, Jean Luc Bersillon · Advances in chemistry series · 1988
Removal of organic substances by metallic salts is one of the most important processes in the water-treatment industry. Some of the subsequent treatment phases depend on the efficiency of the coagulation-flocculation phase. Development of new coagulant-flocculant agents is one way to improve the removal of organic compounds by coagulation. A new generation of aluminum (Al 13 ) and iron hydroxides is being developed by prehydrolyzing aluminum or iron chloride salts to form active species. These polymers have greater reactivity than alum in removing organic material when the solution pH is lower or higher than the sweep flocculation zone. In acidic solutions (pH 6.5 by adsorption onto large particles. The polycations are stable over pH and time. Their structure is open and loose (fractal), ensuring a large available surface area for complexing or adsorbing molecules. The stability constants of organic compound-Al polycation complexes are higher than the stability constants of organic compound-Al or Fe monomer complexes. Prehydrolyzed coagulant-flocculant agents can be designed to adapt the treatment to specific raw-water characteristics.