BOF steel slag as a low-cost sorbent for vanadium (V) removal from soil washing effluent

Abstract

Soil washing is an effective remediation method to remove heavy metals from contaminated soil. However, it produces wastewater that contains large amounts of heavy metals, which lead to serious pollution. This study investigated the removal of vanadium (V) from synthetic soil washing effluent using BOF steel slag. The effects of particle size, slag dosage, initial pH, and initial vanadium concentration on removal behavior were studied. Adsorption kinetics and isotherms were also analyzed. The results showed that the vanadium removal efficiency increased as the steel slag particle size decreased and as the amount of slag increased. The initial pH and vanadium concentration did not play key roles. At the optimum particle size (<0.15 mm) and dosage (50 g/L), the removal rate reached 97.1% when treating 100 mg/L of vanadium. The influence of the washing reagent residue was studied to simulate real conditions. Citric acid, tartaric acid, and Na2EDTA all decreased the removal rate. While oxalic acid did not have negative effects on vanadium removal at concentrations of 0.05–0.2 mol/L, which was proved by experiments using real washing effluents. Considering both soil washing effect and effluent treatment, oxalic acid of 0.2 mol/L is recommended as soil washing reagent.

Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities

“…The acid neutralisation capacity (ANC) of ironmaking and steelmaking slags depends on the slag's chemical and phase composition [62,71,75,76,83,84]. As discussed in Section 3, ironmaking and steelmaking slags materials consist of complex mixture of oxides such as CaO, MgO, FeO, MnO, Al 2 O 3 and SiO 2 .…”

“…As discussed in Section 3, ironmaking and steelmaking slags materials consist of complex mixture of oxides such as CaO, MgO, FeO, MnO, Al 2 O 3 and SiO 2 . These oxides can undergo hydration reactions under aqueous conditions, thereby increasing their alkalinity, adsorption capacity and chemical precipitation ability for metal ions [62,76,84]. Ironmaking and steelmaking slags also contain significant amounts of lime (e.g., 30-50 wt.…”

“…Based on surface models, Dimitrova [70] proposed the adsorption process to involve surface complex formation, precipitation, irreversible ion exchange, interaction of dissolved components of the slag with metal ions and the subsequent deposition of such products on slag adsorbent surfaces. Due to the complexity of adsorbent-adsorbate interactions, it is therefore important to understand the dissolution mechanisms of slags and their components in order to fully interpret the reactivity of slags and/or individually dissolved components of the slag with adsorbates [62,71,75,76,83,84].…”

“…The quantity of adsorbate per unit mass of adsorbent (i.e., adsorption capacity, mg g −1 ) to be taken up, kinetics and extent of adsorption vary depending on the type and physicochemical characteristics (e.g., specific surface area, pore size distribution and active-surface properties) of the adsorbent employed. These parameters are also a function of the experimental conditions employed (e.g., ionic strength, types and concentration levels of adsorbates, mixing time, competing adsorbates, agitation rate and temperature) [42,62,67,[69][70][71][84][85][86][87]. This subsection briefly discusses the previous studies on the topics, focusing mainly on the adsorption capacity of slags.…”

Microbial Community Responses to Vanadium Distributions in Mining Geological Environments and Bioremediation Assessment

“…For remediation, vanadium has to be removed from these matrices to avoid negative ecological impacts. Conventional adsorption is often employed, but can only transfer vanadium in aqueous phase to solid medium, which may lead to secondary pollution (Gao et al, ). In addition, there are three oxidation states of vanadium in the natural environment: vanadium (III), vanadium (IV), and vanadium (V) (Carpentier et al, ).…”