Inorganic metal polymers: preparation and characterization

Abstract

It is possible to produce stable preparations of partially neutralized aluminum chloride solutions in which cationic aluminum polyelectrolytes predominate, but attempts to produce similar stable preparations containing cationic iron(III) polyelectrolytes were unsuccessful. One method to improve the effectiveness of inorganic metal coagulants in water treatment is to partially neutralize concentrated metal salt solutions prior to their addition to the raw water and thus preform polymeric metal species, the actual coagulants. In this way coagulant chemistry can be controlled and proper solution conditions for the formation of desired coagulant species can be maintained. This article compares polymeric preparations of aluminum and ferric chloride salts with respect to preparation parameters and the extent and stability of polymerization.

Modified Inorganic Polymer Flocculant-PFSi: Its Preparation, Characterization and Coagulation Behavior

“…It increases only slightly with increase of B. Compared with the results of PFCl (Gray et al, 1995;Tian and Tang, 1989), the same trend of species distribution is observed. The increase of basicity promotes mainly the amount of Fe c with little yield of Fe b .…”

“…Because of their superior efficiency and relatively lower cost compared with traditional coagulants such as aluminum or iron salts, IPFs are becoming the main water and wastewater treatment reagents, with production and applications on a large scale in Japan, Russia, West Europe and China presently. The USA has also paid much attention to it in recent years (Tang, 1990;AWWA, 1989;Dentel, 1991;Gray et al, 1995).…”

“…Being tailor-made to contain desired more powerful coagulating species, pre-produced IPFs are successful in surpassing the effectiveness of inorganic metal salts and in remedying certain difficulties experienced with seasonal changes in surface water quality (Tang and Stumm, 1987;Gray et al, 1995;Bottero, 1990;Dempsey et al, 1984;Van Benschoten and Edzwald, 1990a, b). Since the application of aluminum-based coagulants was questioned for their potential toxicity (Lewis, 1989), the needs of ironbased coagulants both on their quality and quantity are increased.…”

Hydrolyzed Al(III)-clusters. II: Speciation transformation and stability of Al13 aggregates

“…Compared with the traditional coagulants, IPFs can give markedly improved coagulation effects, and show many advantages such as low dosage, efficient sedimentation, lower sludge volume and flexibility to various water quality conditions [1][2][3]. Among the IPFs, polyaluminum chloride (PACl) is the most efficient, widely applied coagulant and has a mature production technology.…”

Hydrolyzed Al(III) clusters: Speciation stability of nano-Al13

“…Compared with the traditional coagulants, IPFs can give markedly improved coagulation effects, and show many advantages such as low dosage, efficient sedimentation, low sludge volume and flexibility to various water quality conditions (Gray et al, 1995;Tang, 1998;Solomentseva et al, 1999;Wang and Tang, 2001;Wang et al, 2002). Therefore, IPFs have the potential to become the main reagents for water and wastewater treatment.…”