Optimization of Removal of Cadmium (II) using Response Surface Methodology

Abstract

A huge quantity of wastewater is generated and dumped directly into the natural environment. Industrial wastewater recycling is common in India and is mainly used for agriculture in the surrounding areas. This has led to high levels of cadmium and other heavy metals in the air, water, and soil. Natural adsorbents provide an effective solution for wastewater treatment. Wooden objects can be used to remove heavy metals from contaminated water. The current investigation attempts to remove cadmium from the cadmium-containing aqueous solution using the root of Calotropis Procera. The adsorption process was developed with batch studies to quantify the removal of cadmium (Y) using 3 flexible process variables namely, pH, residence time (CT), and adsorbent dose (AD). Interaction between variables, a 20 (23) central composite design (CCD) was developed using the response surface method (RSM). The results of the adsorption verification tests were performed and show excellent compliance with the model prediction. The value of F (550.78) and the return coefficient (R2) of 0.9796 proved the validity of the improved quadratic model.
 HIGHLIGHTS
 
 Cadmium (Cd-II) is a neuro-toxic substance, which gets easily introduced, assimilated into the food chain/natural habitat, and is responsible for severe health problems
 The agricultural waste and biomass i.e. roots of Calotropis Procera was used to treat heavy metals and Cadmium (II) from the wastewater
 The advanced RSM and Central Composite Design (CCD) have been employed for the design of experiments
 DOE is employed with three process parameters viz., pH, residence time and adsorbent dosage to optimise the process
 The results obtained from this investigation indicate that Calotropis Procera is a promising natural adsorbent for the treatment of effluents with Cd (II) ions
 
 GRAPHICAL ABSTRACT