Chromium is a toxic heavy metal with a high recalcitrant and carcinogenic nature even at very low concentrations. In the current investigation, systems thinking analysis is adopted to understand the deleterious effects of chromium on the environment. Hazardous chromate ions are effectively been remediated from industrial discharges by employing the robust adsorbent prepared from marine algae, Gracilaria Rhodophyta Biochar. The combined effect of physicochemical factors such as contact time, pH, biochar dosage and initial chromate concentration on adsorption performance is analyzed by adopting the statistical Response Surface Methodology. At the optimum operating conditions of pH: 2–4; GRB dosage: 0.3 g/100 mL; contact time: 90 min; initial chromate concentration: 60 mg/L and temperature: 30 °C ± 2, an amount of 19.6 mg/g of chromate ions are removed by the developed adsorbent. The characterization results showcased the efficiency of biochar towards the adsorption of chromate ions from wastewater. The adsorption phenomenon follows the Langmuir isotherm model and pseudo-second-order rate kinetics. The investigation of selectivity reveals that the developed adsorbent has a good selectivity for Cr(VI) even with the presence of competing ions in the same medium. The developed robust technology can be successfully applied for the adsorption of toxic chromate ions from contaminated industrial samples.