Development of solid waste of tofu industry immobilized on silica surface as adsorbent for the adsorption of Cd (II) using method of continuous flow column

The aim of this research is to determine the removal efficiency of Cd (II) based on the pH variation and the optimum pH on the batch method, the adsorbent height variation and flow rate in continuous flow column which using tofu solid waste industry which was immobilized silica as adsorbent, also to characterize and to identify functional groups of the absorbent using the FTIR analysis. The pH variation used was 2,3,4,5, and 6. Adsorbent height variation used was 2 cm and 4 cm. Then, variation of flow rate used was 5 ml/min and 10 ml/min. Determination of pH optimum was done using One-Way Anova analysis and continued with Duncan test and descriptive analysis based on the table and graphic. The analysis data of the removal efficiency of Cd (II) in continuous flow column was explained by the descriptive analysis. The pHPCZ was 8.4. The pH optimum was 6 with the removal efficiency 48.14%. The removal efficiency of Cd (II) in continuous flow column for the adsorbent height variation 2 cm and 4 cm which were 38,22% and 43,42% respectively. The removal efficiency of Cd (II) in continuous flow column for the flow rate 5ml/min and 10ml/min each by 38.22% and 39.01%. The result of FTIR analysis of the adsorbent conducted before the adsorption shown that there were functional groups of C=O (vibrate at 1651.07 cm-1), Si-O-Si (462.92 cm-1 and 1095.6 cm-1), O-H (3425.58 cm-1), and N-H (3749.62 cm-1). While, the result of the FTIR analysis after the adsorption shown that there were Si-O-Cd (956.72 cm-1) and Cd-N (412.78 cm-1).