Equilibrium modeling of cadmium biosorption from aqueous solution by compost

Area of Science:

• Environmental Science
• Environmental Chemistry
• Materials Science

Background:

• Metal contamination, particularly cadmium (Cd), poses significant environmental and health risks due to its non-biodegradable nature.
• Aquatic ecosystems are vulnerable to toxic heavy metal pollution from industrial effluents.
• Effective and sustainable remediation strategies are crucial for mitigating these environmental issues.

Purpose of the Study:

• To investigate the potential and feasibility of using fruit and vegetable compost for cadmium (Cd) biosorption from aqueous solutions.
• To evaluate the influence of various parameters on Cd biosorption efficiency.
• To assess compost as a cost-effective adsorbent for heavy metal remediation.

Main Methods:

• Batch biosorption experiments were conducted to study the effects of initial Cd concentration, compost biomass, pH, contact time, and temperature.
• Cd sorption and removal percentages were measured under varying experimental conditions.
• Fourier Transform Infrared (FTIR) spectroscopy was used to analyze the functional groups involved in biosorption.
• Langmuir adsorption isotherm model was applied to analyze the equilibrium data.

Main Results:

• Cd biosorption was significantly influenced by initial Cd concentration, sorbent biomass, pH, contact time, and temperature.
• Optimal Cd sorption and removal (45-99%) were achieved at pH 6 and 28°C, with rapid sorption within 4 hours reaching equilibrium at 19 hours.
• The Langmuir adsorption isotherm model provided a good fit for the experimental data, indicating a maximum sorption capacity (qmax) of 6.35-7.14 mg/g.
• FTIR analysis suggested that hydroxyl and carboxyl groups on the compost surface facilitated Cd biosorption via ion exchange and complexation.

Conclusions:

• Fruit and vegetable compost demonstrates high potential as a cost-effective biosorbent for cadmium removal from aqueous solutions.
• Optimal conditions for Cd remediation using compost were identified as pH 6, 0.5 g/100 mL biomass, and 28°C.
• Compost offers a sustainable and efficient approach for heavy metal remediation in contaminated water bodies.