1. Evaluation of a New Arsenic Adsorbing Resin (WASP) Dr. Robert Stanforth, Ng Aik Teng and Woo Su-Fang National University of Singapore July 2002

2. Introduction A Singapore Company (OSES) has developed a new arsenic adsorbing resin (WASP) Tested to determine properties and effectiveness Both column and batch studies used

3. Column Studies 1000 mg/L Arsenate solution Column 1.2 m, 2.85 L, 35 ml/min flow Parameters tested –pH –Ionic Strength –Residence time As concentration reduced from 1000 mg/L to 0.001 mg/L using two columns

6. Batch Studies 0.5 g resin/100 mL, 1 hr, 18 RPM shaker Parameters tested Arsenic speciation Arsenic concentration pH Ionic strength (higher ionic strength enhanced adsorption) Reaction time (reaction almost complete within 1 hour)

10. Conclusions Resin very effective under optimal conditions pH-adsorption profiles similar to metal oxides Capacity of 35 – 50 g As/kg Difficult to regenerate resin Ionic strength effects mixed – needs further study Resin has good potential