Adsorption of phosphine in off-gas of phosphorus sludge utilization using a molecular sieve 5A

In order to utilize phosphorus sludge comprehensively, phosphine (PH3) in the off-gas of sodium hypophosphite production from phosphorus sludge was adsorbed with a molecular sieve 5A. Effects of adsorbent preparation and operating conditions were analyzed. The results showed that 5A molecular sieve could significantly enhance the adsorption ability after NaCl impregnation. The adsorbent modified by 0.3 M NaCl was applied in the adsorption of PH3, and the best adsorption efficiency was obtained under the following conditions: calcination temperature (300 degrees C), drying temperature (110 degrees C), adsorption temperature (20 degrees C) and carrier gas flow-rate (10 ml/min). SEM and XPS analysis showed that adsorption of PH3 on modified 5A molecular sieve was mainly physisorption. In conclusion, modified 5A molecular sieve can be used in the adsorption of PH3 on phosphoric sludge utilization.