Effective recovery of some precious metals by using alternative quaternary amine types of anion-exchangers prepared from biofuel-extracted microalgal residues

Recovery of Precious Metals Using Microalgae Waste

“…In the present work, three kinds of modified gels were prepared by immobilizing three types of functional groups onto polymer matrices of microalgae residue: dithiooxamide (DTO), polyethyleneimine (PEI), and two kinds of quaternary ammonium (QA) compounds (triethyl-and trimethyl-ammonium), which are abbreviated as DTO, PEI and QA gels (or TMA and TEA gels), respectively, hereafter [9][10][11]. Although, as mentioned earlier, roughly mentioning, microalgae residue is mixture of proteins and carbohydrates, or polysaccharides such as cellulose and hemicellulose, these functional groups are considered to be immobilized onto polymer matrices of polysaccharides.…”

“…This microalga comprises 36 % lipid, 33 % proteins and 19 % carbohydrates. By using the residue of this microalgae after extracting biofuel, two types of adsorption gels were prepared; one was prepared in a simple manner by treating in boiling concentrated sulfuric acid for cross linking for the selective recovery of gold, while others were the microalgal residue chemically modified by immobilizing some functional groups for the recovery of palladium and platinum [8][9][10][11].…”

“…Effect of hydrochloric acid concentration on adsorption of various metal ions on (a) TMA and (b) TEA gels[11].Figures 13 and 14 show the adsorption behaviors of DTO and PEI gels for precious metals such as palladium(II) and platinum(IV) and base metals such as zinc(II) and copper(II) from various concentrations of hydrochloric acid solutions. As shown in…”

“…Effect of hydrochloric acid concentration on adsorption of various metal ions on DIAION PA312resin[11].…”

“…Adsorption isotherms of palladium(II) and platinum(IV) from 0.1 mol/L hydrochloric acid solution on TEA gel[11].Figures 17 and 18show adsorption isotherms of palladium(II)…”