Remoção de vermelho básico de um efluente têxtil simulado: um caso de aplicação da cáscara de arroz

Introduction. The growing development of several chemical industries that use dyes for their basic processes has brought an alarming increase of dyed effluents, which not only are aesthetically deteriorated but physically and chemically affected because processes like photo synthesis, given a reduced sun light transmission and its harmful consequences, can not be well done and that affects all of the life forms living in the ecosystem. Dye removal by the use of adsorption with agricultural remains as adsorbent material is gaining relevance as an innovative alternative to treat the dyes. It is efficient and cheap, and has a positive environmental impact because it uses materials that are easy to get and are usually underused. Objective. To evaluate the adsorption capacity of rice husks in the removal of the basic red (RB46) dye, and characterize the structure of this material. Materials and methods. The best conditions to reach an efficient adsorption were evaluated under a discontinuous system and a univariate method and included the initial value of the pH, the size of the particle, the adsorbent´s dose, the dye´s concentration and the contact time. The RB46 content was determined by an ultraviolet-visible spectrophotometry method. Results. Removal rates of about 91% at a 8.0 pH with a particle size between 0.5-0.75 mm, a 3.0 mg/L dose, a dye 20 mg/L concentration and a 90 min of agitation time. Conclusions. Rice husks have a great capability to remove the RB46 industrial dye. Therefore, it is a promising material to scale this strategy for the treatment of industrial effluents