Biosorption potential of Diplotaxis harra and Glebionis coronaria L. biomasses for the removal of Cd(II) and Co(II) from aqueous solutions

The focus of this study is the investigation of the removal ability of cadmium(II) and cobalt(II) ions from aqueous solution by a natural and low-cost biosorbents developed from local and abundant plants; Diplotaxis harra and Glebionis coronaria L. Biosorption experiments were carried out as function of solution pH, biosorbents dosage, contact time, initial metal ion concentration and temperature. The effect of some major inorganic ions including Na+, K+, Mg2+, Ca2+ and Al3+ on the biosorption was also investigated. Experimental results show that, the biosorption process is very rapid and the biosorption yield increases with an increase in biosorbents dosage. Maximum biosorption was occurred at pH between 6.5 and 7.5. Kinetic data were tested using pseudo-first-order and pseudo-second-order kinetic models. The best fit was obtained with the pseudo-second-order kinetic model. Metal uptake increased with the increase in the initial concentration. Equilibrium data were correlated to Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. Biosorption isotherms for cadmium was best fitted with Langmuir model. Whereas, the biosorption of cobalt was best correlated to Freundlich model. The temperature did not have much influence on the performance of biosorption. FTIR analysis indicates that functional groups present on the surface of the biomasses are involved in metals biosorption.