Investigation of aluminum removal from aqueous solutions using agricultural residues

Nowadays, water pollution has become one of the most important environmental problems in the world. Heavy metals in the waste waters have become an important issue because of their negative effects on natural habitats and vibrants. Aluminum is one of the most abundant heavy metals in waters. In generally, chemical techniques are used for effective removal of aluminium mainly by many industries. These techniques are preferred because of their easy application. However, the chemical techniques have disadvantages such as high cost and generation of toxic slurries that are difficult to eliminate. At this stage, the biotechnological techniques which are inexpensive, easy to use and eco-friendly can be used. The aim of the present study is to investigate aluminium adsorption performance of biosorbents which basically available as agricultural residues. For this purpose; banana peel, lemon peel, sesame seed cake and safflower seed cake were used as biosorbents which are eco-friendly, alternative, non-conventional materials for investigation of heavy metal removal. The effects of process parameters such as pH, biosorbent dose and contact time were investigated using Design Expert 9.0 software. Besides, the most suitable adsorption isotherm models and kinetic models were examined according to the data obtained from the adsorption experiments for each biosorbent used. In the present study; after evaluation of the experimental data obtained from the adsorption studies; aluminum removal using banana peel, lemon peel and safflower seed cake were found as 98.02%, 93.76% and 97.7%, respectively, at pH 6, 0.25 g amount of biosorbent, 30 min of contact time. Moreover, using sesame seed cake, aluminum removal was found as 98.64% at pH 4, 0.25 g amount of biosorbent, 30 min of contact time. In the present study; after evaluation of the experimental data obtained from the adsorption studies; among agricultural residues used, aluminum removal using sesame seed cake was found as 98.64% at pH 4, 25 °C temperature, 0.25 g amount of biosorbent, 30 min of contact time. The maximum adsorption capacity value, Qmax, for sesame seed cake was calculated as 12.315 mg/g. Aluminum removal using banana peel, safflower seed cake and lemon peel were found as 98.02%, and 97.7%, 93.76%, respectively, at pH 6, 25 °C temperature, 0.25 g amount of biosorbent, 30 min of contact time. The maximum adsorption capacity values, Qmax, for banana peel, safflower seed cake and lemon peel were calculated as 11.041, 9.0367 ve 7.8678 mg/g, respectively.