No abstract

In this study, as industrial waste, prina was used as an adsorbent substance with its natural and thermally modified form. The prina used in the study was taken as waste material from an olive oil factory in Ayvalık, Turkey. In this study, the removal possibilities of the toxic effect of crystal violet dye found in various industrial wastewaters with prina adsorbent were investigated. By using the pyrolysis method at 600 °C, the biochar form of prina was obtained. Natural and biochar prina and crystal violet (CV) dye have been tried under different adsorption conditions. For this purpose, experiments were carried out at different prina dosages, initial dye concentrations and contact times. The highest removal efficiencies are around 75% in natural prina, while the biochar is around 99% in prina. Also, concentration studies were applied to Langmuir and Freundlich adsorption isotherm models. As a result of the isotherm study, it was seen that the adsorption mechanism was suitable for Freundlich isotherm model. The contact time removal studies were applied to pseudo-firstorder, pseudo-second-order and intraparticle diffusion kinetic models, and adsorption was found to be fit with the pseudo-second-order kinetic model. According to the experiment results, it was observed that the thermal treatment caused a significant increase in the removal efficiency. It was found that it is an efficient adsorbent material that can be used to remove the CV dye from the aqueous solutions.

Heavy metal contamination is a primary concern worldwide and it is discharged from the industrial wastewater to a large amount of heavy metal receiving environments. In recent years, the effective use of agricultural by-products is definitely a major challenge in waste management. The fact that agricultural residues are more easily obtained and cheaper than commercial adsorbents makes it attractive. In this study, removal of zinc from industrial wastewater using natural and thermally modified (biochar) walnut shells as biosorbent was investigated. It was tried to remove zinc in aqueous solutions with different concentrations by using walnut shells at different rates. The effects of initial concentration, contact time, adsorbent dosage. In addition, adsorption isotherms and kinetics were also studied. With the modified form of the walnut shell, up to 98% zinc removal efficiency was obtained. Also, adsorption was observed to be consistent with pseudo-second kinetics and Freundlich isotherm. The results showed that the modified walnut shell in zinc removal was a potential adsorbent. The adsorption of zinc, onto walnut shells was found to fit Freundlich isotherm. The results obtained in the tests with wastewater showed the potential use of walnut shells for the removal of zinc.