Application of Modified Spent Mushroom Compost Biochar (SMCB/Fe) for Nitrate Removal from Aqueous Solution

Author: mycolabadmin
10/21/2021
View Source

Summary

This research developed a new material made from leftover mushroom compost mixed with iron to clean water polluted with nitrate, a common problem in farming areas. The material works by attracting and trapping nitrate particles, and when tested, it successfully removed up to 19.88 mg of nitrate per gram of the material used. The best results occurred at neutral pH levels and after two hours of contact time. This affordable, environmentally friendly solution could help communities improve their water quality without expensive chemical treatments.

Background

Nitrate pollution from agricultural runoff and industrial wastewater is a significant environmental and public health concern, causing harm to aquatic life and potentially leading to methemoglobinemia in humans. Traditional nitrate removal methods such as ion exchange, electrodialysis, and catalytic denitrification are costly and energy-intensive. Biochar, derived from agricultural waste pyrolysis, offers a promising low-cost alternative for water treatment, but unmodified biochar is ineffective for removing negatively-charged anions like nitrate due to its negatively charged surface.

Objective

This study aimed to synthesize and evaluate a modified spent mushroom compost biochar (SMCB/Fe) impregnated with iron(III) chloride for removing nitrate ions from aqueous solutions. The research investigated the physicochemical properties and adsorption mechanisms of SMCB/Fe under various conditions including pH, contact time, adsorbent dosage, and competing anions.

Results

Maximum nitrate adsorption (19.88 mg/g) was achieved at pH 5-7, 120 minutes contact time, and 2 g/L adsorbent dosage. Nitrate sorption kinetics followed the pseudo-second-order model (R²=0.99) better than pseudo-first-order (R²=0.86). The Langmuir isotherm model provided the best fit (R²=0.996), indicating monolayer adsorption on homogeneous surfaces. Co-existing anions (phosphate, sulphate, chloride) reduced nitrate adsorption, with phosphate showing maximum inhibitory effect.

Conclusion

Modified spent mushroom compost biochar (SMCB/Fe) is an effective, cost-efficient, and environmentally friendly adsorbent for removing nitrate from aqueous solutions through physical adsorption mechanisms. The material demonstrated comparable or superior performance to other iron-impregnated biochars and showed potential for practical water treatment applications. Future studies should explore biochar modification with other metals like magnesium and investigate removal of organic contaminants and field-scale applications.

Published in:Toxics,
Study Type:Experimental Study,
Source: PMID: 34822667, DOI: 10.3390/toxics9110277