Assessment of performance and environmental friendliness of a sorbent-based remediation method for heavy metal and metalloid contaminated soils

Abstract

The contamination of natural ecosystems with heavy metals and metalloids (HMMs) primarily results from anthropogenic activities. Consequently, ongoing efforts are dedicated to the development of technologies aimed at restraining the mobility of HMMs and expediting chemical reactions that convert pollutants from mobile to immobile states. Addressing the reclamation issue always necessitates the selection of the most promising and effective type of reclamation work, as well as justification of land prioritization for reclamation purposes. In terms of performance and future potential, the sorbent-oriented approach, grounded in the concept of “green” utilization of man-made waste as a raw material for creating novel composite sorbents, is gaining traction for land reclamation in disturbed areas. In international practice, diverse environmental risk assessment methods are employed to substantiate the necessity for and prioritize reclamation efforts.The aim of the present study is to evaluate established conventional methods for assessing the risks associated with environmental harm. Additionally, this research aims to assess the efficacy and ecological compatibility of the composite sorbents developed by the author. This evaluation will be conducted by assessing and comparing the levels of potential environmental risks or risks of environmental damage subsequent to the application of these sorbents.The objectives of this study are as follows: 1) to explore the theoretical aspects of HMMs: including the formulation of a definition, investigation onto the origins of HMMs, examination of HMMs’ toxicity, and identification of prevalent methods for evaluating the environmental risks associated with HMMs; 2) to evaluate the effectiveness of established methods for assessing the environmental risks posed by HMMs; 3) to assess the efficacy and environmental sustainability of the composite sorbents developed by the author. This evaluation will involve an examination and comparison of the levels of potential environmental risks and the risks of environmental damage subsequent to the a pplication of these sorbents.The research subject: the mining allotment within the Levikhinskoye mine (classified as an environmental disaster site) is investigated as a disturbed land ecosystem, encompassing industrial waste dumps containing HMMs.The research hypothesis aims to establish the viability of “green” waste utilization from industrial sources as a raw material for composite sorbents used in land reclamation, without escalating the environmental damage. The conducted experiments revealed that sorbents composed of peat/water treatment sludge (at a ratio of 20/80 wt. % with natural moisture content) and peat/diatomite/water treatment sludge (at a ratio of 5/15/80 wt. % with natural moisture content) exhibited the highest level of performance, surpassing an overall efficiency of 89%. A sorbent composed of peat/diatomite (at a ratio of 25/75 wt. % with natural moisture content) demonstrated an overall efficiency of 67.7%. The estimated environmental risks (ER and ED) after the application of the proprietary composite sorbents, which include water treatment sludge, exhibited an average reduction of 89.5% and 88%, respectively.