Enhanced Zn(II) adsorption by chemically modified sawdust based biosorbents

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Heavy metals in industrial effluents pose significant risks to aquatic ecosystems and human health.
• Sawdust is an abundant, low-cost biosorbent material readily available in developing nations.
• Effective treatment of wastewater containing zinc ions is crucial for environmental protection.

Purpose of the Study:

• To investigate the efficacy of modified sawdust biosorbents for zinc ion (Zn(II)) removal from wastewater.
• To compare the performance of boiled (SDB), formaldehyde-modified (SDF), and sulfuric acid-modified (SDS) sawdust.
• To optimize adsorption parameters and elucidate the adsorption mechanism.

Main Methods:

• Preparation and characterization of three sawdust-derived biosorbents (SDB, SDF, SDS) using morphological and functional analyses.
• Adsorption experiments using simulated wastewater and industrial effluents to determine Zn(II) removal efficiency.
• Optimization of process parameters, including pH and adsorbent dosage, and kinetic studies.

Main Results:

• SDS exhibited a porous structure with a high surface area (498.873 m²/g), superior to SDB and SDF.
• Key functional groups (-OH, -C=O, -NH) were identified as crucial for Zn(II) binding.
• SDS demonstrated a high equilibrium adsorption capacity of 45.87 mg/g for Zn(II) removal from industrial effluents at pH 6.0.

Conclusions:

• Sulfuric acid-modified sawdust (SDS) is a highly effective biosorbent for Zn(II) sequestration from industrial wastewater.
• SDS offers a cost-effective and sustainable solution for heavy metal removal in small-scale industrial settings.
• The adsorption process follows pseudo-second-order kinetics, indicating multilayer formation.