Efficient phosphate recycling by adsorption on alkaline sludge biochar

Large amounts of septic tank sludges from sanitation facilities are either landfilled or illegally dumped into the natural environment, leading to environmental pollution and waste resources. This issue calls for advanced methods recycle such as sustainable adsorbents phosphorus, e.g., in agriculture, context circular economy. Here, we hypothesized that alkaline sludge biochar could be an efficient adsorbent phosphate wastewater. We first prepared raw by pyrolysis at 500 °C. Then, 800 °C mixtures potassium hydroxide (KOH) 3/1, 4/1 5/1 mass ratios. studied properties scanning electron microscopy, X-ray diffraction Fourier transform infrared spectroscopy, quantified adsorption phosphates biochars. Results show highly increases with KOH content, 27.83 mg/g 42.51 KOH-biochar. trend is explained increase surface area 64.214 m2/g 82.901 KOH-biochar, improvement structural morphology KOH-biochars. Overall, appears a promising wastewaters.