To solve the problem of methyl orange (MO) dye wastewater pollution, TiO 2-montmorillonite composite (TiO 2-MMT) and Bi 20 TiO 32montmorillonite composite (Bi 20 TiO 32-MMT) were synthesised by the sol-gel method, and they were used for photocatalytic degradation of MO solution. The results showed that TiO 2 in TiO 2-MMT existed as the anatase type, and Bi 20 TiO 32 in Bi 20 TiO 32-MMT existed as the tetragonal crystal type. When the dosage of the composite was 0.50 g/l, the initial concentration of the MO solution was 20 mg/l, and the pH was 3, the decolourisation rate of MO solution using TiO 2-MMT treating was 87.11%, and it reached 98.50% after Bi 20 TiO 32-MMT treating. When Bi 20 TiO 32-MMT was reused four times, the decolourisation rate of the MO solution was only reduced by 3.5%. The photocatalytic degradation between MO solution and Bi 20 TiO 32-MMT complied with the pseudo-first-order kinetic equation. Holes and superoxide radicals interacted directly with MO during photocatalytic degradation, which reduced the probability of hole-electron recombination, and improved the photocatalytic degradation property of Bi 20 TiO 32-MMT. Bi 20 TiO 32-MMT has excellent stability property, which makes it a good composite in the treatment of dye wastewater.
In this study, the composite of Ti‐pillared montmorillonite‐mixed activated carbon (TPM‐AC) was prepared by the water immersion method, and the adsorption of Cd2+ was studied under static conditions. A series of single experiments were conducted to determine the effects of the solution pH, adsorption time, initial Cd2+ concentration, and solution temperature on adsorption performance. The adsorption kinetics, isotherms, and thermodynamics behaviours of Cd2+ onto TPM‐AC were investigated. The results showed that the Brunauer–Emmett–Teller specific surface area and pore volume of TPM‐AC are increased, the crystallinity is greatly improved, and porous structural material with a large specific surface area is formed. The adsorption of Cd2+ by TPM‐AC is excellent and better than that of AC and TPM. The adsorption of Cd2+ by TPM‐AC, AC, and TPM can be described by the pseudo‐second‐order kinetic equation, and the adsorption isotherm is more consistent with the Langmuir isotherm model. The RL values of the dimensionless separation constants are all between 0 and 1, indicating that adsorption of Cd2+ is a relatively easy adsorption process. The values of thermodynamic parameters indicated that the adsorption is a reverse spontaneous and endothermic process.
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