Modified materials based on layered minerals as ameliorants for the remediation of podzol in the industrial barren

Layered silicates, such as serpentine and vermiculite, have properties that make it possible to use materials based on them as components of environmental technologies. The possibility of soil remediation in industrially contaminated area, formed due to the long-term exposure to emissions from copper-nickel production (Monchegorsk, Murmansk region), was studied. Two materials were used as ameliorants in our study: expanded vermiculite and granular serpentine sorbent, a waste after using the purification technology of highly concentrated solutions from metals. These materials have a high sorption activity to several metals, a high specific surface area, the ability to retain moisture, and are available in quantities sufficient to work on the remediation of large areas. A study of the physicochemical properties of industrially polluted soil and ameliorants, direct phytotoxicity testing of podzol and its mixtures with expanded vermiculite and the serpentine sorbent (test plants - common oat Avna satva L. and red clover Trifolium pratnse L.) were carried out. The study results showed that the proposed materials were effective additives for increasing the pH of acidic soil, sorption and precipitation of Al and potentially toxic metals - Cu, Ni, Pb, Fe, and improving the soil hydrophysical and agrochemical characteristics. A positive response of test plants to the introduction of ameliorants into industrially contaminated soil was noted.

Preparation of a Highly Porous Clay-Based Absorbent for Hazard Spillage Mitigation via Two-Step Expansion of Vermiculite

Expanded vermiculite (eVMT) has been studied as a risk-free, general-purpose absorbent for liquid hazards due to its excellent thermal and chemical stability. Here, vermiculite was expanded by two steps: exfoliation by 30 wt% H2O2 treatment at 60 °C and subsequent expansion by microwave heating. This two-step expansion produced more homogenously separated concertina-like eVMTs with a higher total pore volume of 7.75 cm3 g−1 than the conventional thermal method. The two-step eVMT was found to be greatly superior to the thermal and commercial silver counterparts in hazardous liquid-uptake performance. The uptake was simply interpreted as a physical infilling process of a liquid into the eVMT pores, and the spontaneous hazard removal with a great capacity was discussed with the large pore volume of two-step eVMT and its suitable pore dimensions for capillary action. As a practical device, a prototype absorbent assembly made of these eVMTs demonstrated the successful mitigation of liquid hazards on an impermeable surface.