Estudos de equilíbrio da adsorção de 2,4 D a partir de soluções aquosas

Abstract

Pesticides contracted among the chemical contaminants in water bodies present in our agroindustrial sources, where the main source is mainly related to agro-industries. In the environment pesticides caused to individuals pesticides, can occur from water bodies, in trophic chains, cause environmental workers and the reduction of the biosphere. The herbicide 2,4 D is in the 2nd place of the most sold pesticides in Brazil, and due to its natural pollution in water and harmful effects on health, it is necessary to develop technologies for its removal. Adsorption is a technique that can be effective for removing pollution from water. Thus, the present work investigates the use of activated carbon and zeolite for the treatment of 2,4 D in water, through the objective of studies of percentage of removal and isotherms, and the comparison with the functionality of materials with surfactants. A study of 2 of the use of activated adsorbent of 1 commercial was elaborated, being determined the 1 gads. Studies for supplies were made for delivery of 1; 2.5; 5; 10 and 15 mg L-1, under constant 4 hours of contact and pH similar to the pH of 2 waters at neutral temperature and temperature. After adsorption, the detection of residual 2.4 D was performed by High Performance Liquid Chromatography coupled to the UV detector. The highest observed values of adsorption capacity at equilibrium were 1.08 mg g-1 for the natural zeolite clinoptilolite, 0.77 mg g-1 for the SDS-functionalized zeolite and 1.30 mg g-1 for the zeolite with CTAB For commercial activated carbon, the maximum value of 11.4 mg g-1 was observed, for carbon functionalized with SDS the values reached 3.54 mg g-1 and for carbon functionalized with CTAB the maximum value obtained was 3.02 mg g-1. The percentage values of removal observed, from highest to lowest, were: 97.7% with activated carbon without functionalization, 64% for carbon functionalized with SDS, 48.4% for carbon functionalized with CTAB, 23.6% using SDS zeolite, 21.6% for zeolite functionalized with CTAB and 12.6% using natural zeolite clinoptilolite. The adjustments of the Langmuir, Freundlich and BET models were applied, where the BET and Langmuir models were the ones that presented the best adjustments to the experimental data. Among the materials studied, adsorption with activated carbon without functionalization proved to be the best alternative for removing this pollutant from the water.