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BACKGROUND: The adsorption removal of phenol onto bentonite that was prepared by the traditional hydrothermal method has been widely studied; especially, surfactant-modified bentonite has achieved an exclusive position on effective removal to phenol. However, the adsorption performance of the bentonite functionalized by double-carbon chain surfactants in a microwave field for phenol is relatively low. The study on the fabrication of organobentonite by microwave-assistance to remove organic pollutants still needs to be investigated. RESULTS:The adsorption performance of bentonite was enhanced after functionalizing with Dihexadecyldimethylammonium Bromide (D1621). FTIR and XRD patterns revealed that D1621 was successfully intercalated into bentonite, and the interval space was increased by 1.54 to 1.84 nm. The optimized preparation condition was obtained at a molar ratio (D1621: Bentonite) of 0.36, solid-liquid ratio (D1621 + Bent: water) of 0.12, microwave mode of Med, and thermal radiation for 6 min based on the indicator of phenol adsorption uptake. An excellent removal rate for phenol was observed at pH 2 to 7 and room temperature in adsorption tests. The adsorption process was spontaneous at room temperature according to thermodynamic parameters, and it agrees with Freundlich (R 2 = 0.9781) and pseudo-second-order (R 2 = 0.9999) models, validating a chemisorption process.CONCLUSION: The D1621-Bent perpetrated by using the microwave-assisted heating method was proven to be a reliable adsorbent for phenol in water. The adsorption performance of bentonite on phenol was remarkably enhanced after the introduction of organic modifiers.

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A low-cost functionalization method was used to treat diatomite, and an efficient adsorbent for ammonia nitrogen was prepared by optimizing the functionalization conditions. The functionalized diatomite (DTCA-Na) was characterized by SEM, EDS, BET, XRD, FT-IR and TG. The results demonstrate that DTCA-Na has excellent adsorption performance after being modified with H2SO4 (60.00 wt.%), NaCl (5.00 wt.%) and calcination at 400 °C for 2 h. While studying the effect of adsorption factors on the removal of ammonia nitrogen, the kinetic and thermodynamic behaviors in the adsorption process were discussed. The removal efficiency of the simulated wastewater with the initial ammonia nitrogen concentration of 10.00 mg/L by the DTCA-Na was more than 80% when the contact time was 60 min, pH was 6-10, the dosage of adsorbent was 1.00 g, the temperature was 25 °C. The adsorption process of ammonia nitrogen was conformed to the pseudo-first-order and Langmuir isothermal model. The removal efficiency of ammonia nitrogen was still above 80% after 5 times adsorption-desorption experiments. The DTCA-Na has a brighter prospect of application in the field of ammonia nitrogen wastewater treatment due to its excellent adsorption performance and low-cost advantage.