Low‐cost, green synthesis and adsorption properties for dyes of novel porous gangue/palygorskite composite microspheres

In this work, gangue/palygorskite composite microspheres were fabricated through spray drying process and activated by calcination treatment. Its microstructure and adsorption capacity for the removal of dye (MB) were also studied, systematically. Results showed that kaolinite, α‐quartz and palygorskite were the major phases in microspheres after proper calcination (lower than 900°C). BET‐specific surface area of the microspheres reached the maximum value of 62.23 m2/g at 700°C, and then decreased with further increasing the heating temperature. In general, composite microspheres showed the largest adsorption capacity of MB after heat‐treated at 700°C. The qmax of MB onto microspheres was 29.9‐51.9 mg/g. The adsorption process of MB onto microspheres was well described by both the pseudo‐second‐order kinetic and Langmuir isotherm model. The composite microspheres also had extraordinary recyclability. This novel microsphere could be employed as a candidate for novel absorbent and filter medium in the practical application for dye treatment in industrial applications.