Cr(VI) Reducing Ability of an L-Ascorbic Acid Loaded Polyamine-type Chelate Resin Derived from Kenaf

The preparation of a polyamine-type chelate resin based on Kenaf, the adsorption of L-ascorbic acid on the above chelate resin, and the reduction of Cr(VI) by the chelate resin adsorbing L-ascorbic acid was studied. Kenaf was pretreated with concentrated hydrochloric acid, and oxidized with potassium permanganate. Carboxylic group generated on Kenaf was reacted with triethylenetetramine to give polyamine-type chelate resin. The optimum pH range for the adsorption of L-ascorbic acid was about 1 to 5. The adsorption capacity by a batch method was 1.55 mmol g−1, and by a column method was 1.98 mmol g−1. Cr(VI) was reduced by using chelate resin with L-ascorbic acid. In the batch method, reducing Cr(VI) in a sulfuric acid solution at 95°C, 6.54 mmol g−1 of Cr(VI) was reduced. This reducing ability is almost the same as the reducing ability of sodium sulfite, which is conventionally used industrially. In the column method, when 100 mg L−1 Cr(VI) in sulfuric acid solution was passed through the above-mentioned resin filling column, the treatment reducing of Cr(VI) abilities were 138 BV (bed volumes) at room temperature and 233 BV at 60°C, respectively.