Biochar （BC） is a potential material for removal of polycyclic aromatic hydrocarbons t^om soil and water, and base modification is a promising method for improving its sorption ability. In this study, we synthesized...Biochar （BC） is a potential material for removal of polycyclic aromatic hydrocarbons t^om soil and water, and base modification is a promising method for improving its sorption ability. In this study, we synthesized a series of base-modified biochars, and evaluated their sorption of phenanthrene. Original biochars were produced by pyrolysis of three feedstocks （rice straw, wood and bamboo） at five temperatures （300~C, 350~C, 400~C, 500~C and 700~C）. Base-modified biochars were further obtained by washing ofbiochars with base solution. The base soluble carbon （SC） was extracted from the supernatant, which were only obtained from biochars pyrolyzed at low temperatures （ 〈 500~C） and the content was decreased with the increase of pyrolysis temperature. The SC content between different feedstocks followed the trend office straw〉wood〉bamboo when same pyrolysis conditions were applied, It was tbund that base modification improved the sorption of phenanthrene on biochars that SC could be extracted from （extractable-BCs）. However, base treatment but had limited effects for biochars that no SC could be extracted from. It suggested that base modification improved the sorption of phenanthrene to extractable-BCs by removing the SC and thus increasing the surface area and hydrophobicity. Therefore, base modification was suggested to be used in modifying extractable-BCs.展开更多
文摘Biochar （BC） is a potential material for removal of polycyclic aromatic hydrocarbons t^om soil and water, and base modification is a promising method for improving its sorption ability. In this study, we synthesized a series of base-modified biochars, and evaluated their sorption of phenanthrene. Original biochars were produced by pyrolysis of three feedstocks （rice straw, wood and bamboo） at five temperatures （300~C, 350~C, 400~C, 500~C and 700~C）. Base-modified biochars were further obtained by washing ofbiochars with base solution. The base soluble carbon （SC） was extracted from the supernatant, which were only obtained from biochars pyrolyzed at low temperatures （ 〈 500~C） and the content was decreased with the increase of pyrolysis temperature. The SC content between different feedstocks followed the trend office straw〉wood〉bamboo when same pyrolysis conditions were applied, It was tbund that base modification improved the sorption of phenanthrene on biochars that SC could be extracted from （extractable-BCs）. However, base treatment but had limited effects for biochars that no SC could be extracted from. It suggested that base modification improved the sorption of phenanthrene to extractable-BCs by removing the SC and thus increasing the surface area and hydrophobicity. Therefore, base modification was suggested to be used in modifying extractable-BCs.
