Application of Cellulose-Based Solid Acid in Absorption of Heavy Metal Ions from Printing Waste Water

Traditional printing (lithography, gravure, letterpress, PCB etc.) produce a large of industrial wastewater from washing printing plate, rubber cloth and circuit boards corrosion. These waste water mainly contain copper ion and silver ions, which is difficult to process under acid condition. Taking effective methods to remove the metal ions in waste water has become a hotspot in research. In this paper, cellulose-based solid acid (CCSA) was prepared using microcrystalline cellulose and 98% concentrated sulfuric acid as raw materials. The characterization of CCSA was first analyzed by acid strength and Fourier-transform infrared spectrometer (FTIR). Infrared spectrogram display that sulfonic group was successfully connected on cellulose-base. Acid value measurement indicates that the total acidic group of CCSA decline from 1.87 to 1.02 mmol/g with carbonization temperature rise. Subsequently, effects of carbonization temperature on adsorption performance to Cu2+ and Ag+ were investigated. The result shows that carbonization temperature at 400 °C reach best absorptivity of 80 mg/g (Cu2+) and 247 mg/g (Ag+) respectively. However, with carbonization temperature rise to 600 °C absorption quantity was just 66 mg/g (Cu2+) and 158 mg/g (Ag+) respectively.