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Nanomesoporous silica SBA-15 was prepared by hydrothermal method. The samples were characterized by powder X-ray diffraction and scanning electron microscopy. The fibrous particles with a diameter of 333 ± 10 nm were obtained. Nanoporous mesoporous SBA-15 was used as an adsorbent to adsorb Cd 2+ in water body. The effects of conditions such as acidity were studied, and the optimized adsorption conditions were obtained. The results showed that when the pH value was 5.0, the temperature was 25 ± 1 °C and the adsorption time was 40 min, the nanomesoporous SBA-15 had the best adsorption effect for Cd 2+ and the adsorption rate was reached 73.28% and the adsorption capacity was 9.84 mg/g. Study found that the adsorption is the quasi-second-order kinetic model, which belongs to the Freundlich adsorption type. The results of adsorption thermodynamics showed that when the temperature is 25-55 °C, the adsorption is spontaneous exothermic reaction, ∆G 0 < 0, the adsorption enthalpy change ΔH 0 = − 54.732 kJ/mol, the adsorption entropy change ∆S 0 = − 129.343 J/(mol K). The effects of nitric acid and hydrochloric acid on desorption were investigated, respectively. The results showed that the desorption effect of 0.1 mol/L nitric acid as desorbent was better than that of hydrochloric acid. At desorption for 10 h, the desorption rate was the highest, reaching 65.56%.

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Mesocellular foam (MCF) silica molecular sieve material was successfully synthesized using a hydrothermal method. X-ray diffraction, infrared spectroscopy, low nitrogen adsorption–desorption, scanning electron microscopy, and transmission electron microscopy (TEM) characterization techniques were used to characterize the material. Low temperature nitrogen adsorption–desorption method showed that pore size of the synthesized MCF was 12 nm. TEM study showed that the synthesized MCFs had honeycomb structure pores, which can be good for the absorbance of dye organic macromolecule substances. This work studied the adsorption of crystal violet by MCF and the results showed that when the adsorptive conditions were pH = 9.0, MCF:crystal violet = 150:1, and when the contact time was 10 min at room temperature of 25 ± 1 °C, the adsorption rate reached 99.71% and adsorption capacity was 6.646 mg/g. This study found that the adsorption is a Freundlich type, it is a multimolecular layer adsorption, and it belongs to the pseudo-second-order kinetic model. According to the ΔG0 obtained from adsorption thermodynamics, when the temperature is 25–40 °C, the adsorption enthalpy change ΔH0 = −25.65 kJ/mol, ΔG0 &lt; 0, the adsorption is an exothermic reaction and can spontaneously occur. The adsorption entropy change ΔS0 = 5.54 J/(mol·K) and the entropy of system increased.

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