Cationic Surfactant-Modified Tetraselmis sp. for the Removal of Organic Dyes from Aqueous Solution

Abstract

The modification of the Tetraselmis sp. algae material (Tetra-Alg) with surfactant Cethyltrimethylammonium Bromide (CTAB) yielded adsorbent Tetra-Alg-CTAB as an adsorbent of methyl orange (MO) and methylene blue (MB) solutions. The characterization of the adsorbent used an infrared (IR) spectrometer to identify functional groups and Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX FEI Inspect-S50, Midland, ON, Canada) to determine the surface morphology and elemental composition. Methyl orange and methylene blue adsorption on the adsorbent Tetra-Alg, Tetraselmis sp. algae-modified Na+ ions (Tetra-Alg-Na), and Tetra-Alg-CTAB were studied, including variations in pH, contact time, concentration, and reuse of adsorbents. The adsorption of MO and MB by Tetra-Alg-CTAB at pH 10, during a contact time of 90 min, and at a concentration of 250 mg L−1 resulted in MO and MB being absorbed in the amounts of 128.369 and 51.013 mg g−1, respectively. The adsorption kinetics and adsorption isotherms of MO and MB and Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB tend to follow pseudo-second-order kinetics models and Freundlich adsorption isotherms with each correlation coefficient value (R2) approaching 1. Due to the modification with the cationic surfactant CTAB, anionic dyes can be strongly sorbed in alkaline pH due to strong electrostatic attraction, while MB is more likely to involve cation exchange and hydrogen bonding. The reuse of Tetra-Alg-CTAB was carried out four times with adsorption percent > 70%, and the adsorbent was very effective in the adsorption of anionic dyes such as MO.

In Situ Ca‐ and Mg‐ Codoped Biochar Derived from Tobacco Stem for Phosphate Adsorption and Desorption

“…And lots of natural adsorbents such as fungi, bacteria, yeast, and algal biomass were used for the removal of anionic contaminants from water and wastewater. [4,5] Biochar is a solid obtained by the pyrolysis of biomass materials at high temperatures under low oxygen or oxygen isolation conditions and has the advantages of a large specific surface area, high porosity, rich functional groups, and good adsorption performance. [6] Owing to its abundance and renewability, biomass rich in lignin and cellulose (such as agricultural straw, branches, and peel) is currently used as a raw material to prepare biochar and is widely used in adsorbents, catalysts, carbon dioxide storage, soil remediation, and slow-release fertilizers.…”