Preparation of Water-Resistant Supramolecular Compounds ({[BHMTA]2 [CdI4]} (1), {[BHMTA]2 [Pb2I6]}n (2) and {[BHMTA]2 [β-Mo8O26]·[H3O+]2·[H2O]3}(3) (BHMTA = N-benzylhexamethylenetetramine bromide) and the Application in the Removal of Methylene Blue in Aqueous Solution

The existence of residual organic dyes in water resources or wastewater treatment systems with industrial wastewater as the main source is a major environmental problem that is difficult to solve. Three eco-friendly and water-resistant supramolecular compounds were prepared using BHMTA (BHMTA = N-benzyl hexamethylenetetramine bromide) as a template. In the limited environment of supramolecules, organic dyes are efficiently removed in water. Compound {[BHMTA]2 [β-Mo8O26]·[H3O+]2·[H2O]3} (3) can achieve high efficiency by capturing more than 90% of methylene blue dye content even at very low concentrations (1 × 10−5 mol/L). The effects of the amount of adsorbent, temperature, and acid and alkali on the adsorption of organic dyes were systematically studied. The adsorption behavior of compound 3 fits well with the quasi-second-order kinetic model and the Langmuir model. The maximum adsorption capacity of methylene blue (MB) (950 mg/g) is higher than the most reported adsorbent. More importantly, compound 3 still had a higher adsorption effect after three cycles. These results indicate that the compound treatment wastewater has potential application prospects.