The characterization of biochars derived from rice straw and swine manure, and their potential and risk in N and P removal from water. (1st September 2019)

• Record Type: Journal Article
• Authors: Luo, Ling; Wang, Guolan; Shi, Guozhong; Zhang, Mengting; Zhang, Jing; He, Jinsong; Xiao, Yinlong; Tian, Dong; Zhang, Yanzong; Deng, Shihuai; Zhou, Wei; Lan, Ting; Deng, Ouping
• Is Part Of: Journal of environmental management. Volume 245(2019)
• Page Start: 1
• Page End: 7
• Publication Date: 2019-09-01
• Subjects: MgCl2 modification -- Manure-derived biochar -- Plant residue derived biochar -- Pollutant removal -- Pollutant release; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2019.05.072
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Nowadays, the plant residual derived biochars have been widely applied to remove nitrogen (N) and phosphorus (P) from water. However, the application of animal manure derived biochars in N and P removal was less studied. To compare the different efficiency and risk of plant residual- and animal manure-derived biochar in removing N and P from water, this study chose rice straw and swine manure as representative to produce biochar at 700 °C, and modified the produced biochar by MgCl2 . Then, the characteristics, removal efficiency and release of N and P of biochars were investigated. The results showed swine manure-biochars generally had higher ash content and cation exchange capacity (CEC), but lower pH and surface area relative to rice straw-biochars. Besides, MgCl2 modification reduced the ash content and surface area of both raw biochars, whereas the pH, CEC and pore size were enhanced. Furthermore, this work demonstrated that ammonium and nitrate could be removed by all biochars to certain extent, and MgCl2 modified biochars generally had higher removal efficiency. However, none of phosphate removal was achieved by all biochars. Additionally, the release of ammonium, nitrate and phosphate from biochars was observed, suggesting there might be a risk for applying biochars in N and P removal from water. Notably, the MgCl2 modification seemed to accelerate N and P release from biochars. This work provided important information that the production and modification of biochars should be carefully designed for higher removal efficiency of pollutants. Meanwhile, the risk of released pollutants as well as the release mechanisms should be paid more attention in the future. Graphical abstract: Image 1 Highlights: Swine manure biochar showed higher CEC but lower surface area than rice straw biochar. MgCl2 enhanced CEC and pore size, but reduced surface area of both raw biochars. All biochars could remove NH4 + and NO3 −, and MgCl2 elevated the removal efficiency. None of PO4 3− was removed by these biochars. All biochars released N and P, suggesting a possible source of N and P in water.