Characterization and Potential Use of Biochar for the Remediation of Coal Mine Waste Containing Efflorescent Salts

Abstract

Abstract:In open pit coal mining, soil and vegetation are removed prior to the start of mining activities, causing physical, chemical, and microbiological changes to the soil and landscape. The present work shows the results of an integrated study of the remediation of mine waste with a high level of salt contamination in areas of the Cesar Department (Colombia), employing biochar as an amendment. Physical-chemical properties including Munsell color, texture, pH, electrical conductivity, water-holding capacity, cation exchange capacity, metal content, organic carbon, sulfates, extractable P, and total nitrogen were characterized both in the soils contaminated with mine residues and the biochar sample. A high concentration of sulfates, calcium, iron, and aluminum and a significant presence of Na, followed by minor amounts of Mg, K, Cu, and Mn, were observed in efflorescent salts. X-ray diffraction indicated a high presence of quartz and gypsum and the absence of pyrite and Schwertmannite in the efflorescent salt, while showing broad peaks belonging to graphene sheets in the biochar sample. Soil remediation was evaluated in Petri dish seed germination bioassays using Brachiaria decumbens. Biochar was shown to be effective in the improvement of pH, and positively influenced the germination percentage and root length of Brachiaria grass seeds.

Nitrogen recovery in reclaimed mine soil under different amendment practices in tandem with legume and non‐legume revegetation: A review

“…Jain et al (2020) recommended the use of biochar for phytostabilization of highly acidic mine spoils. Employing alkaline biochar (palm oil residues) as an amendment showed potential to remediate salt-contaminated coal mine spoil containing only 1300 mg kg −1 total N and favoured germination and root growth of Brachiaria decumbens (Muegue et al, 2017).…”

Synthesis, Characterization and Ecotoxicity Evaluation of Biochar-Derived Carbon Dots from Spruce Tree, Purple Moor-Grass and African Oil Palm

“…Pyrolysis is a method with complete absence of oxygen and process temperatures around 300-700 • C. The three main products from pyrolysis are synthesis gas (syngas), bio-oils, and biochar [6]. Syngas and bio-oils are widely used for electricity, heat, and biofuel production while biochar is used in bioremediation and amendments processes in soils [6][7][8]. However, the use of biochar is limited due to the variability of the physicochemical properties that depend on the original biomass and the thermal process conditions.…”

Effect of rice hull biochar treatment on net ecosystem carbon budget and greenhouse gas emissions in Chinese cabbage cultivation on infertile soil

“…With a high carbon content and alkalinity, biochar improves soil traits and crop productivity [12]. Various studies have underscored its positive impact on diverse crops, including maize, soybean, chickpea, wheat, bell pepper, and tomato [13][14][15][16][17][18]. Biochar research extends beyond agriculture to environmental management and carbon-neutral technology [19].…”