典型生物炭的亲水和疏水性特征及其影响因素OA

To explore the hydrophilicity and hydrophobicity characteristics of biochar and their determining factors,biochars were obtained from six typical feedstocks under three pyrolysis temperatures and washed using two methods including acid-alkali washing and water washing.The contact angles of different biochars and their relation to biochar properties were analyzed by using sessile drop method and random forest analysis.The results showed that:1)The biochar pyrolyzed at 300 ℃ was hydrophobic with contact angles greater than 120°,whereas the biochar at 700 ℃ was hydrophilic with contact angles less than 60°.The contact angles of biochar pyrolyzed at 500 ℃ varied with feedstock type:Those from sawdust,rice husk,and chicken manure were greater than 120° while those from maize straw,cow dung,and pig manure were less than 60°.2)The results of random forest analysis revealed that the pore volume,dissolved organic carbon,specific surface area,and H content were significantly related to biochar contact angle.3)As the pyrolysis temperature increased,dissolved organic carbon and H decreased while the pore volume and specific surface area increased,leading to the conversion of biochar from hydrophobic to hydrophilic.4)Acid-alkali washing and water washing both decreased the biochar hydrophobicity.In conclusion,the low-temperature and high-temperature pyrolyzed biochars exhibit distinct hydrophobicity and hydrophilicity,respectively,and water washing has application potential in reducing biochar hydrophobicity.