Wang Xingpeng, Jiang Chao, Li Huiyu, Tian Weiliang, Ahmed Saeed, Feng Yongjun
State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China.
College of Chemistry and Chemical Engineering, Tarim University, Alar 843300, China.
Materials (Basel). 2024 Apr 26;17(9):2034. doi: 10.3390/ma17092034.
Attapulgite (APT) is widely used in wastewater treatment due to its exceptional adsorption and colloidal properties, as well as its cost-effectiveness and eco-friendliness. However, low-grade APT generally limits its performance. Here, a colloid mill-assisted ultrasonic-fractional centrifugal purification method was developed to refine low-grade APT. This process successfully separated and removed impurity minerals such as quartz and dolomite from the raw ore, resulting in a refined APT purity increase from 16.9% to 60% with a specific surface area of 135.5 m∙g. Further modifying of the refined APT was carried out through the hydrothermal method using varying dosages of cetyltrimethylammonium chloride (CTAC), resulting in the production of four different APT adsorbents denoted as QAPT- ( = CTAC mole number) ranging from 0.5 to 5 mmol. Using Congo red (CR) as the target pollutant, the QAPT-5 sample exhibited the best adsorption capacity with the maximum quantity of 1652.2 mg∙g in a neutral solution at 30 °C due to the highest surface charge (zeta potential = 8.25 mV). Moreover, the QAPT-5 pellets (~2.0 g adsorbent) shaped by the alginate-assisted molding method removed more than 96% of 200 mL aqueous solution containing 200 mg∙L CR and maintained this efficiency in 10 adsorption-elution cycles, which exhibited the promising practical application.
凹凸棒石（APT）因其优异的吸附和胶体性能、成本效益及生态友好性而被广泛应用于废水处理。然而，低品位的APT通常会限制其性能。在此，开发了一种胶体磨辅助超声分级离心提纯方法来提纯低品位APT。该工艺成功地从原矿中分离并去除了石英和白云石等杂质矿物，使提纯后的APT纯度从16.9%提高到60%，比表面积为135.5 m∙g。通过水热法使用不同剂量的十六烷基三甲基氯化铵（CTAC）对提纯后的APT进行进一步改性，得到了四种不同的APT吸附剂，记为QAPT-（=CTAC摩尔数），范围从0.5到5 mmol。以刚果红（CR）作为目标污染物，QAPT-5样品在30℃的中性溶液中表现出最佳的吸附容量，最大吸附量为1652.2 mg∙g，这是由于其具有最高的表面电荷（zeta电位=8.25 mV）。此外，通过海藻酸钠辅助成型法制备的QAPT-5颗粒（约2.0 g吸附剂）对200 mL含200 mg∙L CR的水溶液的去除率超过96%，并在10次吸附-洗脱循环中保持该效率，显示出良好的实际应用前景。
