Premium
Arsenic removal by ferric chloride
Author(s) -
Hering Janet G.,
Chen PenYuan,
Wilkie Jennifer A.,
Elimelech Menachem,
Liang Sun
Publication year - 1996
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.1996.tb06541.x
Subject(s) - arsenic , ferric , adsorption , chemistry , coagulation , chloride , sulfate , hydrous ferric oxides , inorganic chemistry , water treatment , environmental engineering , organic chemistry , psychology , sorption , psychiatry , engineering
Source water composition affects removal efficiency. Bench‐scale studies were conducted in model freshwater systems to investigate how various parameters affected arsenic removal during coagulation with ferric chloride and arsenic adsorption onto preformed hydrous ferric oxide. Parameters included arsenic oxidation state and initial concentration, coagulant dosage or adsorbent concentration, pH, and the presence of co‐occurring inorganic solutes. Comparison of coagulation and adsorption experiments and of experimental results with predictions based on surface complexation modeling demonstrated that adsorption is an important (though not the sole) mechanism governing arsenic removal during coagulation. Under comparable conditions, better removal was observed with arsenic(V) [As(V)] than with arsenic(III) [As(III)] in both coagulation and adsorption experiments. Below neutral pH values, As(III) removal–adsorption was significantly decreased in the presence of sulfate, whereas only a slight decrease in As(V) removal–adsorption was observed. At high pH, removal–adsorption of As(V) was increased in the presence of calcium. Removal of As(V) during coagulation with ferric chloride is both more efficient and less sensitive than that of As(III) to variations in source water composition.