Adsorption characteristics of recycled construction waste particles for ammonia-nitrogen in rainfall runoff

Abstract

In order to explore the removal method of ammonia nitrogen in water and solve the disposal problem of construction waste.After the construction waste is crushed,the particles with different sizes (recycled particles for short) are screened out for ammonia nitrogen adsorption in simulated wastewater.SEM,EDS and BET were used to characterize the recycled particles, and the effects of different external factors on adsorption efficiency and ammonia nitrogen removal rate under dynamic environment were investigated.The results show that：The surface of the recycled particles was rough and had a large number of pores.The adsorption process follows the pseudo-second kinetics and Langmuir isotherm adsorption model;the maximum adsorption capacity of the recycled particles of 0-2mm, 2-3mm, 3-5mm and 5-10mm were 0.1169mg/g, 0.1213mg/g, 0.1200mg/g and 0.1182 mg/g, respectively;the optimal pH was 6-7 ； Na+ had a slight effect on ammonia nitrogen adsorption.In the static adsorption experiment,the large size recycled particles have a higher adsorption capacity,while in the dynamic adsorption experiment,the small recycled particles have a higher adsorption capacity.