Abstract:

In this research, the removal of malachite green, which is a toxic and carcinogenic dyestuff, which is often used in aquaria and in the dyeing of products such as cotton and fiber, from wastewater by using Siirt/Koçpınar clay was investigated. In the first stage of our study, the adsorbent was used without any modification (K1) in the necessary studies, then the same processes were repeated with the nitric acid modified adsorbent (K2). In the study, initial pH (2.0 – 8.0 range), adsorbent amount (0.05 g - 1 g range), concentration (50 ppm - 150 ppm range), temperature (298 K - 323 K range) and contact time (0 min. - 120 min interval) was also investigated and the data obtained were applied to Langmuir, Freundlich, DR isotherm models. As a result of the study, the best efficiency was obtained in the studies using 0.2 g adsorbent with the initial value of pH 5, and as a result of the study, 63.05% for K1 adsorbent and 91.99% removal for K2 adsorbent were achieved. As a result of isotherm calculations, the correlation coefficient of the Freundlich isotherm model was found to be greater than 0.98 at all temperatures. The D-R adsorption free energy calculated with the help of the D-R isotherm model was found to be less than 8 kJ/mol for both clays and all temperatures. The negative Gibbs free energy values found as a result of thermodynamic calculations showed that the adsorption process occurred spontaneously.

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