Avaliação de materiais alternativos como adsorventes na remoção de ureia em efluentes industriais

Abstract

High levels of urea contamination in water bodies are increasing over the years and may cause eutrophication in aquatic environments, which promotes ecological imbalance, decrease of aquatic species and spread of diseases. Alternative methods are being used for the removal of nitrogenous compounds in effluents; one example is the adsorption technique. On the basis of that information, were analyzed the urea effluent of a big logistics company in Araguari and a similar effluent was made, composed of water and urea, to be used in the tests of this study. This study aims to analyze the urea removal potential of four alternative adsorbent materials: zeolite, blast furnace slag, expanded clay and recyclable construction waste. These materials were analyzed according to the fixed-bed column methodology for four different throughput volumes of effluents, the efficiency of urea adsorption was calculated according to the removal of the Chemical Oxygen Demanding of the initial effluent. The material that obtained the highest percentage of urea removal was the recyclable construction waste (RCW) with a maximum removal of 39.16%. In addition, this adsorbent material presented a rupture curve closer to the ideal if compared to the other materials analyzed. For a better analysis of the behavior of the RCCR as an adsorbent, two experiments were carried out using the batch equilibrium isotherm methodology and it can be concluded that the maximum adsorption capacity of RCW was approximately 5.27 mg/g and 7.24 mg/g, respectively. These values occurred in both tests when the urea concentration in the synthetic effluent was 460 mg/L.