OBTAINING OF ADSORBENTS USING CITRIC ACID MODIFICATION OF PLANT WASTE

Abstract

Currently, information about the influence of factors for the obtaining modified plant waste using citric acid on their adsorption properties towards to cationic dyes is few and contradictory. In this paper experiment was designed to find the optimum variables such as citric concentration, modification temperature and modification time for the obtaining of adsorbents from ligno-cellulosic plant waste (barley straw and corn stalks) by their modification and using for removal cationic dyes (methylene blue and malachite green). The response of the designed experiment was evaluated through cationic dyes removal efficiency. For optimization of plant waste modification response surface methodology was utilized where full factorial central composite design (as 23) has been employed. It allows to carry out a minimum number of experiments, as well as to analyze the interaction between the variables. The empirical models regarding actual variables of plant waste modification for cationic dye removal efficiency were obtained using MINITAB 18 software as regression equations. The values of R2 and R2adj for dyes removal efficiency were found and their values verified the linearity between the model’s calculated results and experimental data for cationic dyes removal efficiency. Predicted values thus obtained were closed to experimental value indicating suitability of the models. The optimum points for citric concentration, modification time and temperature were found to be 0.78 M, 210 min and 393 K, respectively. Under these conditions, the modified adsorbents from barley straw and corn stalks removal efficiency should have maximum of 93-95 %. The physico-chemical characteristics of unmodified and modified barley straw and corn stalks prepared at optimum points for citric concentration, modification time and temperature were analyzed.

Keywords

• модифікація
• рослинні матеріали
• адсорбція
• катіонні барвники
• центральний композитний план