Pyrolysis of animal manure under nitrogen atmosphere: An environment protection way to obtain animal manure biochar for high-efficient adsorption of uranium (VI)

For reducing the damage of pig manure (PM) to the ecological environment, three different biochar materials were prepared by pretreating PM with different reagents (distilled water, hydrochloric acid and sodium hydroxide). It was found that the oxygen content of PMBC-OH- reached 34.4%, which was much higher than that of PMBC (21.1%) and PMBC-H+ (14.1%), indicating that the oxygen-containing functional groups onto PMBC-OH- were abundant. Further, the adsorption properties of the three kinds of biochars were discussed with uranium (VI) as the adsorbate. Compared with PMBC (369.9 mg/g) and PMBC-H+ (53.3 mg/g), PMBC-OH- possessed excellent performance and its adsorption capacity reached 952.5 mg/g, which was much higher than that of other reported biochar materials. Meanwhile, PMBC-OH- could completely remove uranium (VI) from solution with low uranium (VI) concentration to achieve the standard of wastewater discharge. Briefly, the method of preparing biochar by pretreating PM with sodium hydroxide could effectively improve the utilization rate of PM and reduce the damage of nutrients in PM to ecological environment. Based on the above analysis, PMBC-OH- possessed the potential to be applied for removing uranium (VI) from wastewater.