Amendment of Caulerpa sertularioides marine alga with sulfur-containing materials to accelerate Cu removal from aqueous media

Abstract

This study reports a new approach of alga amendment in a live mode. The Caulerpa sertularioides alga was modified with sulfur-containing materials of methionine (C₅H₁₁NO₂S) and sodium sulfate (Na₂SO₄) to more concentrate the sulfur content of the yielded biomass (adsorbent). The simple and amended C. sertularioides alga was fully characterized with FTIR, SEM, EDX, BET, BJH, and pH_zpc techniques. The copper adsorption from aqueous media was done by three adsorbents of C. sertularioides-simple (CSS), C. sertularioides-Na₂SO₄ (CSN), and C. sertularioides-C₅H₁₁NO₂S (CSC). The parameters of pH (2–6), adsorbent dosage (2–10 g/L), and contact time (3–80 min) were optimized at 5, 5 g/L, and 60 min, respectively. According to Langmuir isotherm (the best-fitted model), the maximum adsorption capacity of CSN (98.04 mg/g) was obtained 2.4 times higher than CSC (40.73 mg/g) and 9.5 times higher than CSS (10.29 mg/g). The Cu adsorption process by the adsorbents was best-fitted pseudo-second-order kinetic model. The CSN, CSC, and CSS biomasses were successfully reused 5, 4, and 4 times, respectively. The thermodynamic study revealed that the copper adsorption process by CSN is exothermic and non-spontaneous. Finally, the suitability of adsorbents prepared from algae was tested by cleaning a simulated wastewater.

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