Modification of the properties of nonconforming zeolite raw materials from deposits in Eastern Transbaikalia in order to obtain effective sorbents for wastewater treatment

The article presents the results of investigation of various modifications based on nonconforming zeolite raw materials rocks of the Holinsky depozit with a low klinoptilolite content (50-55%), which substantiates the feasibility of their involvement in the production of sorbents effective for wastewater treatment from oil products and heavy metal ions. Various methods of modifying zeolites have been studied: with high-silicon compounds (hexamethyldisilazalone and tetraethoxysilane), as well as with a sulfur polymer based on by-products of the production of epichlorohydrin. The investigation of microstructures of obtained samples was carried out using scanning electron spectroscopy (SEM), X-ray phase analysis (XPA) using powder X-ray diffractometry. The fixation of modifiers on the zeolite surface has been proven by IR spectroscopy and energy-dispersive X-ray spectroscopy (EDS). The sorption of heavy metal ions such as nickel and zinc on modified zeolites has been proven by IR, EDS, and inductively coupled plasma atomic emission spectrometry (ICP-AES). To prove the sorption of oil products, IR methods were used, as well as differential scanning calorimetry and thermogravimetry. Сlass of hazard (IV) for spent sorbents was established by biotesting using Daphnia magna Straus and Chlorella vulgaris Beijer .