Removal of Nickel and Cadmium using Diatomite, Silt, Sunflower stem and Cement (Green Concrete Components)

Adsorption is one of a common treatment applied in heavy metal removal. Recently, studies of low-cost adsorbent are intensively gain attention to the scientist were usually waste product from industrial, agricultural and food production which produced abundantly. Since most of the structures, ponds, and drainage pipelines are made of concrete, the use of adsorbent concrete can be an effective way to remove pollutants, especially heavy metals from wastewater. In this research, diatomite and sunflower stems were used as concrete additives to adsorb cadmium and nickel from wastewater as well as materials that could maintain and even increase the strength, durability, and stability of concrete in water and wastewater structures. Diatomite was replaced with part of the cement and sunflower replaced with part of aggregates used in concrete. The adsorption of Nickle and cadmium by concrete components (cement, silt, diatomite and sunflower stem) was investigated. Cement was able to remove nickel and cadmium completely. Other components of the concrete also have a good ability to remove nickel and cadmium. The maximum adsorption capacities of Ni and Cadmium for diatomite, silt, and sunflower stem were 2.85 and 1.88, 2.61 and 2.82, 18.45 and 6.82 mgr/gr, respectively. Metal adsorption onto adsorbents was evaluated by Langmuir and Freundlich isotherms. Results indicate that both Langmuir and Freundlich isotherm models are suitable. Concrete pieces removed cadmium completely, but in nickel absorption, the control sample had the best performance