5种活性生物炭对水体低浓度氮、磷吸附效果研究

Study on the Adsorption Effect of 5 Activated Biochars on Low-concentration Nitrogen and Phosphorus in Water

随着水污染防治措施的实施和加强,低浓度污染水体的治理成为水污染治理的重要部分。为探究不同活性生物炭对水体中低浓度氮(N)、磷(P)的吸附特性,选取紫茎泽兰(Ageratina adenophora)、锯木屑、甘蔗渣、咖啡壳和烟梗等5种云南较为丰富的生物质为原料,硫酸锌(ZnSO_(4))为活化剂,制备得到5种活性生物炭,并对污染水体中低浓度N、P进行模拟吸附试验。结果表明:活性生物炭比表面积和孔径分布均优于未活化的普通生物炭,其中锯木屑活性炭比表面积增加了10.3倍,达(1534.87±23.21)m^(2)·g^(−1),蔗渣活性炭和紫茎泽兰活性炭比表面积均增加了9.5倍,分别为(1225.89±21.21)m^(2)·g^(−1)和(1260.50±14.31)m^(2)·g^(−1),且孔径以过渡孔为主,更有利于吸附水体中N和P。活性生物炭较未活化的普通生物炭对N、P的最大吸附容量分别从720 mg·kg^(−1)和371 mg·kg^(−1)提高至1207 mg·kg^(−1)和675 mg·kg^(−1)。不同活性生物炭对N、P的吸附受pH、COD质量浓度、炭水比等因素的影响。偏酸性条件有利于吸附N,偏碱性条件有利于吸附P;水体COD浓度与活性生物炭脱N除P的效果正相关;炭水比与活性生物炭脱N除P的效果负相关;水体中同时存在N、P污染物时更有利于活性生物炭对N、P的去除,表现出协同作用。

With the implementation and strengthening of water pollution control measures,the treatment of low-concentration polluted water has become an important part of water pollution control.To investigate the adsorption effect of different activated biocars on low-concentration nitrogen(N)and phosphorus(P)in water,5 activated biocars were prepared from 5 biomass abundant in Yunnan Province,including crofton weed(Ageratina adenophora),sawdust,sugarcane bagasse,coffee shell and tobacco stem,with zinc sulfate(ZnSO_(4))as an activator,and were used for the simulated adsorption test on low-concentration N and P in polluted water.The results showed that the specific surface area and pore size distribution of activated biocars were superior to those of unactivated common biochar.The specific surface area of sawdust activated biocar increased by 10.3 times,was(1534.87±23.21)m^(2)·g^(−1),and the specific surface area of bagasse activated biocar and crofton weed activated biocar increased by 9.5 times,was(1225.89±21.21)m^(2)·g^(−1)and(1260.50±14.31)m^(2)·g^(−1),respectively.The pore size was mainly transition pore,which was more conducive to the adsorption of N and P in water.The maximum adsorption capacity of N and P increased from 720 mg·kg^(−1)and 371 mg·kg^(−1)to 1207 mg·kg^(−1)and 675 mg·kg^(−1),respectively,compared with unactivated common biochar.The adsorption of N and P by different activated biocars was affected by such factors as pH,COD mass concentration and biochar-water ratio.The acidic condition was favorable for N adsorption,and the alkaline alkaline condition is favorable for P adsorption.COD mass concentration was positively correlated with the effect of N and P removal by activated biochar.Biocar-water ratio was negatively correlated with the effect of N and P removal by activated biochar.The presence of N and P pollutants in water was more conducive to the removal of N and P by activated biochar,showing a synergistic effect.