One-pot green synthesis of magnetic adsorbent via Anabaena sphaerica and its performance towards Remazol Red dye removal from aqueous media

[Display omitted] •Green approach was adopted using a simple one-pot route.•Novel magnetic biosorbent was obtained via Anabaena sphaerica biomass.•The Fe3O4-biosorbent adsorbs efficiently Remazol Red dye.•The magnetic biosorbent was successfully recovered and reused. A simple one-pot green approach was adopted for synthesizing novel surface-modified Anabaena sphaerica biomass of various functional groups with the superparamagnetic Fe3O4. The preparation strategy was based on the reduction of iron-precursor by the antioxidants released from Anabaena sphaerica during the solvothermal process. The prepared materials were applied for Remazol Red F3B (RR) dye removal. The adsorptive material prepared by 1:3 Anabaena sphaerica to Fe-precursor weight ratio as starting materials heated at 200 °C/48 h removed ∼ 98% of RR dye (10 mg/L) after only 15 min at pH 3. The reusability of the best sample was confirmed for five consecutive runs. Langmuir best described the adsorption equilibrium data, while Elovich's kinetic model best fitted the experiment data even at low adsorbent dosage. Conclusively, the prepared magnetic biosorbents were demonstrated as good adsorbents for water decontamination.