Polymerization reactions in hydrolyzed iron(III) solutions

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

“…Obviously, to preform stable Fe(III) polymers, it needs to cross the first precipitation zone (roughly 0:25B*50:5) and prevent homogeneous amorphous precipitation ðB*> 1:5Þ. Despite numerous investigations, the mechanism of hydrolysispolymerization-precipitation of Fe(III) and the quantitative principles are still not perfectly clear (Van De Woude and De Bruyn, 1983;Melikov, 1987;Khoe and Robins, 1989). The nature and behavior of hydrolysis products are controlled by many factors, such as the components and concentration of the primary Fe(III) solution, pH, components of coexisting anions, temperature, time of aging, traces of contaminants including dust particles, which can seed the precipitation of the solid, preparation methods and other topchemical transformation.…”

Monitoring the hydrothermal precipitation of α-Fe2O3 from concentrated Fe(NO3)3 solutions partially neutralized with NaOH

“…The experimental conditions for the preparation of samples are given in Table 1. The concentrations given in Table 1 correspond to those obtained upon mixing of proper volumes of concentrated Fe(NO 3 ) 3 and NaOH solutions. The starting concentration of AAS in the corresponding precipitation systems was 0.1 M.…”

“…Hydrolyses in the nitrate-and chloride-containing solutions started with the formation of simple iron(III)-hydroxy complexes, continued with the formation of hydroxy polymers and oxo bridges. It was suggested that the polymers formed in the Fe(NO 3 ) 3 solution included no nitrate ion in the polymer chain, whereas the polymers formed in the FeCl 3 solution contained some chloride ions in place of hydroxyl ions. In the Fe 2 (SO 4 ) 3 solutions the FeSO þ 4 complex suppressed the formation of hydroxy polymers and iron basic sulfate was formed instead.…”

“…Bottero et al [2] confirmed the earlier finding [1] by using synchrotron measurements. Khoe and Robins [3] used potentiometric titration to investigate polymerization during the hydrolysis of Fe 3+ solutions in a concentration range of 2 Â 10 À4 -2 Â 10 À2 M. The authors suggested to incorporate Cl À and SO 2À 4 ions into the structure of hydroxy polymers. Matijević the influence of phosphate [20], (c) amidosulfonate [21], and (d) temperature [22] on this crystallization process.…”

“…Musić et al [1] monitored forced hydrolyses of 0.1 M Fe(NO 3 ) 3 , FeCl 3 and Fe 2 (SO 4 ) 3 solutions. Hydrolyses in the nitrate-and chloride-containing solutions started with the formation of simple iron(III)-hydroxy complexes, continued with the formation of hydroxy polymers and oxo bridges.…”