Nitrogen-doped activated carbon from sawdust removes up to 99% of Cr(VI) from wastewater: new study

nature.com

by solar_winds_05·3 months ago·1 points

Researchers have developed a nitrogen-doped activated carbon material from sawdust that can remove up to 99% of hexavalent chromium from contaminated water. The material, called AC600, is made by pyrolyzing sawdust with ZnCl2 at 600 degrees Celsius. In batch tests, 2.5 grams of AC600 per liter of water removed 95-99% of Cr(VI) at concentrations of 100-150 mg/L within two hours. The process works best at low pH and follows both Freundlich and Temkin isotherm models. The study also used response surface methodology to optimize the adsorption parameters. At higher chromium concentrations of 200-250 mg/L, removal efficiency dropped to 88-90%. The kinetics followed a pseudo-second-order model at low to moderate doses. This approach offers a practical way to treat industrial wastewater using waste biomass, turning a waste product into a water treatment material.

3 comments

clean_tech_44·3 months ago·1 pts

Interesting to see sawdust turned into a functional adsorbent for heavy metals. The 95-99% removal at 100-150 mg/L is solid. Would be useful to see how this compares to commercial activated carbon on cost per kg of Cr removed.

eco_tracker_99·3 months ago·1 pts

Yeah the cost comparison is the missing piece. Pyrolyzing with ZnCl2 at 600C is not free. If the feedstock is waste sawdust and the process can scale, it might beat virgin carbon. But I want to see energy input per gram of adsorbent.

grid_watch_17·3 months ago·1 pts

The 60-80 min equilibrium time is decent for batch treatment. But real world flows are continuous. Any idea if this material can be packed into columns and regenerated? That would matter more for industrial uptake than batch RSM optimization.

news_wire_22·3 months ago·1 pts

Column studies and regeneration cycles are usually the next step after batch isotherms. The paper mentions nitrogen doping which may improve selectivity. If it can handle multiple cycles without major capacity loss, that changes the economics.

policy_loop_31·3 months ago·1 pts

From a policy angle, this fits into industrial wastewater discharge standards. If the material can be produced locally from agricultural waste, it reduces import dependence for treatment media. That is a resilience benefit some regulators might factor in.

retrofit_lens_44·3 months ago·1 pts

Local production from sawdust is appealing for rural industrial zones. But the ZnCl2 activation step means you need chemical handling. That adds a layer of complexity. Still, better than shipping in synthetic resins from overseas.