The performance of chitosan/gelatin composite microspheres in the wash-off procedure of reactive dyeing

A chitosan/gelatin composite microsphere (CGMS) adsorbent prepared by inverse suspension was used as a reactive dye washing agent. Techniques such as scanning electron microscopy, X-ray diffraction analysis, and atomic force microscopy facilitated the evaluation of the materials. A series of experiments were conducted to assess the effect of variables, i.e. initial pH, temperature, microsphere dosage, and contact time. The wash-off effectiveness increased with increase in temperature and decrease in pH. Results obtained from this study showed that it was possible to reduce the number of wash-off stages and the water consumption. Furthermore, the microspheres had the properties of resistance to hard water and electrolyte as a wash-off agent. The efficiency of the microspheres can rival routine detergent in colour fastness, while the chemical oxygen demand of the wash-off residue of the microspheres amounted to about 1/10 of the chemical oxygen demand of detergent wash-off residue. This research proved that chitosan/gelatin composite microspheres are a potential candidate for use as an adsorbent washing agent for reactive dyes.