Starch xanthate adsorbents

To address this concern, several organic and inorganic reagents were evaluated as precipitants for heavy metals in a 10-34-0 (N-P2O5-K2O) fluid fertilizer and WPA. Trisodium trithiocyanuric acid (TMT-15), sodium polythiocarbonate (Thio-Red II), and sodium trithiocarbonate (5% Na2 CS3) precipitated arsenic, cadmium, copper, mercury, lead, and zinc from 10-34-0. Ammonium cyanurate was ineffective in removing cadmium from 10-34-0. Thio-Red II and 5% Na2CS3 precipitated mercury, lead, cadmium, copper, and chromium from WPA. A water-insoluble starch xanthate adsorbed mercury, copper, and lead from 10-34-0 and WPA. Sodium sulfide, sodium polysulfide, and potassium ferrocyanide were tested as inorganic precipitants. The polysulfide was twice as effective as the sulfide alone, and concentrations of less than 10 ppm of arsenic, cadmium, mercury, and lead were achieved in 10-34-0. Ferrocyanide reduced the concentrations of cadmium and nickel to less than 10 ppm in WPA. 

Starch Xanthate Adsorbents. Wing and coworkers (12) reported that insoluble starch xanthate was highly effective in adsorbing iron(II) and chromium(III) from synthetic waste water samples. For example, a pH 3.0 waste water with an initial iron(II) concentration of 27,920 mg/L was treated with the starch xanthate and after stirring for 2 h, the residual iron(II) concentration was found to be <1 mg/L. Similar results were obtained for chromium(III), where the chromium(III) concentration of a synthetic waste water sample at pH 3.2 was reduced from 26,000 mg/L to 3 mg/L after stirring for 2 h with the appropriate amount of starch xanthate. 

Mercury, copper, lead, and cadmium can be precipitated from 10-34-0 by adding TMT-15. The TMT-15 and Thio-Red II precipitated at least 94% of the copper and mercury present in the 10-34-0 manganese and chromium were not precipitated. The WI starch xanthate adsorbed mercury, copper, and lead from 10-34-0, while the adsorption of arsenic, cadmium, chromium, manganese, and zinc was negligible. 

Cellulose. Cellulose or starch xanthate cross-linked by titanates can adsorb uranium from seawater (536). CarboxymethylceUulose cross-linked with TYZOR ISTT is the bonding agent for clay, talc, wax, and pigments to make colored pencil leads of unusual strength (537). 

---