Cd diminution through microbial mediated degraded lignocellulose maize straw: Batch adsorption and bioavailability...

Area of Science:

• Environmental Science
• Soil Science
• Bioremediation

Background:

• Cadmium (Cd) contamination poses significant risks to soil health and ecosystems.
• Maize straw is an abundant agricultural residue with potential for soil amendment.
• Microbial degradation can enhance the properties of lignocellulosic materials for environmental applications.

Purpose of the Study:

• To prepare lignocellulose degraded maize straw (LMS) using soil microorganisms.
• To evaluate the efficacy of LMS in attenuating cadmium contamination in polluted soil.
• To investigate the mechanisms of Cd sorption and its bioavailability reduction by LMS.

Main Methods:

• Preparation of LMS through microbial interaction and characterization using FE-SEM, FTIR, BET, elemental analysis, and XPS.
• Batch sorption experiments to determine Cd2+ adsorption kinetics and isotherms (Langmuir and pseudo-second-order models).
• Soil incubation trials to assess the effect of LMS and pristine maize straw (PS) on Cd bioavailability and soil fractions.

Main Results:

• LMS exhibited significant degradation of cellulose (33.03%), hemicellulose (26.7%), and lignin (15.97%) compared to PS.
• LMS demonstrated a higher maximum adsorption capacity for Cd2+ (9.84 mg g-1) than PS (3.30 mg g-1).
• Soil incubation showed a substantial decrease in Cd availability by 34.7% with LMS application, compared to 11.03% with PS, with a shift in Cd fractions towards organic matter and Fe-Mn oxides.

Conclusions:

• Microbial degradation effectively modifies maize straw structure, enhancing its metal-ion complexation ability.
• LMS is a highly effective adsorbent for Cd2+ and a promising amendment for reducing Cd bioavailability in contaminated soils.
• This study highlights LMS as a sustainable and efficient material for the remediation of Cd-polluted matrices.