Attapulgite/bentonite interactions for methylene blue adsorption characteristics from aqueous solution

• Attapulgite/bentonite composites were prepared as adsorbent for MB removal.
• Compared to bentonite, salt resistance and adsorption rate of composite increased.
• Compared to attapulgite, adsorption capacity of composite greatly increased.
• MB loaded adsorbents were not easily desorbed by diluted HCl and NaOH solution.

Attapulgite/bentonite composite adsorbents have been prepared via high-pressure homogenization technique. It was aimed to investigate the synergistic effect of one-dimensional attapulgite and two-dimensional bentonite on the adsorption property for methylene blue (MB) from aqueous solution in this paper. The process parameters affecting adsorption behaviors such as bentonite content, pH of MB solution, contact time and initial concentration were systematically investigated. The results showed that the adsorption capacity of the adsorbents increased with the increase in the content of bentonite while the adsorption rate decreased due to the decrease in the content of attapulgite. The adsorption process could be well described by pseudo-second-order kinetics and Langmuir isotherm model rather than Freundlich and Temkin isotherm models. The MB loaded adsorbents were not easily desorbed with diluted HCl or NaOH solution, and thus can be employed as candidates for organic–inorganic pigments.