Efficient removal of water pollutants by hierarchical porous zeolite-activated carbon prepared from coal gangue and bamboo

The inorganic heavy metal ions (IHMIs) and organic macromolecular pollutants (OMPs) are the two most common pollutants in industrial, agricultural and municipal wastewater. They have greatly threatened the environmental security and human health because of their most notorious toxicity and carcinogenicity. In this study, a composite of zeolite-activated carbon is synthesized taking coal gangue as silicon and aluminum sources and adding bamboo as carbon source through a facile calcining process following a hydrothermal process. The obtained zeolite-activated carbon composite is a kind of hierarchical porous structure, which contains a large number of micro-pores, meso-pores and macro-pores simultaneously. The zeolite-activated carbon with high specific surface area of 879.1 m(2)/g is used to absorb IHMIs and OMPs. It shows high adsorption capacities for copper ions (Cu-2(+), 104.9 mg/g) and Rhodamine-B (Rh-B, 83.34 mg/g). The zeolite with a large number of micro-pores could chain a lot of IHMIs with small diameters, and the activated carbon could allow large size OMPs into its meso-pores and macro-pores. The thermodynamic and kinetic studies indicate that the adsorption of adsorbates onto the zeolite-activated carbon composite is assigned to a monolayer, spontaneous and physical adsorption. Thus the zeolite-activated carbon composite could adsorb the pollutants quickly and desorb them repeatedly. This research not only effectively deals with the IHMIs and OMPs in the waterbody, but also converts the coal gangue into high value-added product. Therefore, this study provides a facile method to synthesize zeolite-activated carbon composite from solid waste and biomass material. The prepared zeolite-activated carbon composite could be selected as a potential candidate for sewage treatment.

无机重金属离子（IHMIs）和有机高分子污染物（OMPs）是工业、农业和城市废水中两种最常见的污染物。由于它们具有极强的毒性和致癌性，极大地威胁了环境安全和人类健康。在本研究中，以煤矸石为硅源和铝源，并添加竹子作为碳源，先经过水热过程，再通过简便的煅烧工艺合成了一种沸石 - 活性炭复合材料。所获得的沸石 - 活性炭复合材料是一种分级多孔结构，同时包含大量的微孔、介孔和大孔。比表面积高达879.1平方米/克的沸石 - 活性炭被用于吸附无机重金属离子和有机高分子污染物。它对铜离子（Cu₂⁺，104.9毫克/克）和罗丹明 - B（Rh - B，83.34毫克/克）表现出高吸附能力。含有大量微孔的沸石可以吸附许多直径较小的无机重金属离子，而活性炭可以使大尺寸的有机高分子污染物进入其介孔和大孔。热力学和动力学研究表明，吸附质在沸石 - 活性炭复合材料上的吸附属于单分子层、自发的物理吸附。因此，沸石 - 活性炭复合材料可以快速吸附污染物并可反复解吸。这项研究不仅有效地处理了水体中的无机重金属离子和有机高分子污染物，还将煤矸石转化为高附加值产品。因此，本研究提供了一种从固体废物和生物质材料合成沸石 - 活性炭复合材料的简便方法。所制备的沸石 - 活性炭复合材料可作为污水处理的潜在候选材料。