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Marine algae, often blooming in abundance and causing pollution, can be effectively managed by transforming it into valuable products like alginate or biochar for water treatment. A recent study explored the use of alginate-modified algal biochar to remove the heavy metal Cr(VI) from water. The research utilized biochar derived from brown algae, Sargassum wightii, combined with sodium alginate to create a new adsorbent for Cr(VI) in water.

The alginate-modified algal biochar blended film was thoroughly examined using methods like FTIR, XRD, TGA, and SEM. It showed a large surface area of 336.82 m²/g, an average pore size of 22.20 cm³/g, and a pore volume of 2.04 cc/g. The study investigated how pH, contact time, and adsorbent dosage influenced the adsorption behavior of Cr(VI) through batch experiments. Results demonstrated a high adsorption capacity, with up to 92% removal efficiency.

Further analysis indicated that Cr(VI) adsorption onto the alginate-modified algal biochar film closely followed the Freundlich isotherm model and that the adsorption kinetics matched the pseudo-second-order (PSO) model with an R² value of 0.999. These findings suggest that the alginate-modified algal biochar film is a promising, low-cost, and environmentally friendly adsorbent for removing Cr(VI) from water.