Ahya, Muhammad Khairil, et al. Desalination and Water Treatment 257 (2022): 220-227.
Sodium Lauryl Sulfoacetate (SLSA), a plant-based anionic surfactant, was used to modify activated carbon (AC) through isolate impregnation in this work. This created SLSA-impregnated activated carbon (SIAC) with tailored surface properties for selective ion removal.
Surface Modification of AC: Virgin AC (2g) was added to 200 mL SLSA solutions at concentrations ranging from 10-175 mg/L. Mixtures were agitated overnight (60°C, 130 rpm), filtered without rinsing, and dried (60°C, 24h). Modified adsorbents were designated as SIACs (e.g., SIAC-75 = 75 mg/L SLSA). Characterization included BET surface area analysis and FT-IR spectroscopy. Batch adsorption tests assessed Zn(II)/Cr(VI) removal efficiency after 6-hour contact.
Key Findings:
· Surface Charge Modification: SLSA's sulfonate groups (OSO3-) imparted a negative surface charge to AC, fundamentally altering adsorption behavior.
· Opposite Removal Trends: Zn(II) removal increased progressively with SLSA concentration, peaking at 31.66% for SIAC-75. Cr(VI) removal decreased steadily with increasing SLSA concentration.
· Electrostatic Mechanism: Negative SIAC surface attracted positively charged Zn(II) ions. Negative SIAC surface repelled chromate ions (CrO42-) from dissociated Cr(VI).
· Porosity Trade-off: SIAC-75 showed the lowest BET surface area (749.51 m2/g) due to SLSA pore occupation, yet achieved highest Zn(II) removal - proving functionality overcomes porosity limitations.
