Vietnamese bentonite with poor quality had been purified before being modified with iron salts to create inorganic bentonite composite (Ben-C). This process increased the specific surface area to 221.83 m2g−1. The test showed that the reactive dye was rapidly adsorbed in about 1 h by the Ben-C and the adsorption efficiency reached its maximum value at a Ben-C content of 3 g/L. Ben-C had been used as an adsorbent for 6 types of textile industrial wastewater. Companies used different kinds of dyes and additives, so the color adsorption time of each wastewater was also different, ranging from 0.25 to 2 h. Adsorption efficiency tended to increase with adsorbent content, but the increased level depended on the type of wastewater. Wastewater color treatment was more effective when the adsorption process was carried out at a low temperature, 20–25 °C. The FTIR spectrum of wastewater also evaluated the effectiveness of wastewater color removal.