Experimental investigation of iron removal from wet phosphoric acid through chemical precipitation process

Integrated Process of Immediate One-Step Lime Precipitation, Atmospheric Carbonation, Constructed Wetlands, or Adsorption for Industrial Wastewater Treatment: A Review

“…Carbonate and hydroxide anions can react with a wide range of cations, leading to the formation of highly insoluble precipitates [72]. For example, the instantaneous conversion of calcium bicarbonates and magnesium bicarbonates into precipitated calcium carbonates (Equation ( 4)) and magnesium carbonates (Equation ( 5)), as well as the transformation of magnesium carbonates into precipitated magnesium hydroxides (Equation ( 6)) [60,63].…”

“…Removal of heavy metals (e.g., Ni, Zn, Fe, Cr, and others) in the form of precipitated hydroxides (Equations ( 9) to ( 12)) or carbonates, as well as their adsorption on calcium carbonate. Metal hydroxide precipitation is highly dependent on pH [67,71,72,79]. [67] Cheese whey wastewater Lime, pH 6 to 13 700-800 rpm for 1 min, 300-400 rpm for 1 min, followed by settling for 24 h.…”

“…Although IOSLM is a simple operation, fast (i.e., high precipitation speed), low-cost (chemical cost and energy requirements) [82,83], and does not contribute to an increase in salinity (unlike some salts used, such as iron and alum [60]) or the formation of toxic secondary pollutants [72], this process leaves the effluent with a high pH [79], the NH 4 + removal is limited [84], and it produces large amounts of sludge [60]. Effluent with a high pH is unsuitable for some sequence treatment processes within a wastewater treatment plant, and calcium carbonate precipitation may occur in the distribution pipelines [79].…”