摘要
剩余污泥和水稻秸秆是典型的城市和农林固体废弃物,都是制备生物炭的理想原料。生物炭制备过程中可能会产生多环芳烃类物质(PAHs)。PAHs的含量及毒性评价可为生物炭的制备及应用选择提供重要的依据。目前,对比不同热解温度下剩余污泥生物炭和水稻秸秆生物炭中PAHs的含量及毒性评价的报道还较少。因此,文章以典型的固体废弃物——剩余污泥和水稻秸秆为原料,在300、400、500、600、700℃下进行热解,采用高效液相色谱法(HPLC)测定生物炭15种典型PAHs(多环芳烃)的含量,并采用毒性当量因子(Toxic Equivalent Factor,TEF)方法评价了生物炭的毒性特征。结果表明,在300—600℃内,污泥生物炭中多环芳烃生成量随热解温度的提高而降低,600℃时达到最低,质量分数为5.344 mg·kg−1,而在700℃下,质量分数达到了252.78 mg·kg−1。当热解温度在300—600℃时,秸秆生物炭中PAHs的质量分数随着热解温度的上升呈现降低的趋势;在600℃时热解无多环芳烃生成;而700℃时仅生成少量多环芳烃。低温热解时,污泥生物炭中更容易产生2环和3环多环芳烃,在高温热解时,则更容易生产4环和5环多环芳烃。热解温度为300—400℃时,污泥生物炭和秸秆生物炭以2环和3环PAHs为主;在热解温度为500—700℃时,污泥和秸秆生物炭中PAHs以4环和5环PAHs为主(600℃秸秆生物炭除外)。在300—600℃热解温度范围内,污泥生物炭的苯并[a]芘毒性当量浓度(TEQBaP)随热解温度增加而下降,600℃时,污泥生物炭的TEQBaP最低,为0.9781 mg·kg−1,而700℃制备的污泥生物TEQBaP最高,可达109.7608 mg·kg−1。300℃秸秆生物炭中3环PAHs对TEQBaP贡献最大,其他温度下制备的污泥和秸秆生物炭中,5环PAHs对TEQBaP贡献最高。热解温度为600℃时,污泥和秸秆制备的生物炭中PAHs含量均最低,且PAHs毒性当量浓度最小。因此,从PAHs含量和毒性角度考虑,600℃可作为
Sewage sludge and rice straw are typical urban and agricultural solid wastes and are ideal raw materials for biochar preparation.Polycyclic aromatic hydrocarbons(PAHs)may be produced during the preparation of biochar.The content and toxicity evaluation of PAHs can provide an important basis for the preparation and application of biochar.At present,investigation on PAHs content and toxicity evaluation between sludge biochar and rice straw biochar at different pyrolysis temperatures had been reported.Thus,two typical solid waste,sewage sludge and rice straw,was pyrolyzed to biochar under the O2-free atmosphere at 300,400,500,600 and 700℃.The content of PAHs in biochar was detected by HPLC and the toxicity of biochar was assessed.The results showed that with the increase of pyrolysis temperature 300‒600℃,the content of PAHs in sludge biochar decreased.The minimum value of PAHs was 5.34 mg·kg−1 at 600℃and the maximum value of PAHs was 252.78 mg·kg−1 at 700℃.For rice straw biochar,with the increase of pyrolysis temperature 300‒500℃,the contents of PAHs in biochar decreased.The PAHs in rice straw biochar from 600℃were not detected and little PAHs were observed at 700℃.The 2‒3 rings PAHs were predominant in sewage sludge and rice straw biochar derived at 300–400℃.Meanwhile,4‒5 rings PAHs were the main components in biochar pyrolyzed at 500–700℃(expect of rice straw biochar at 600℃).The TEQBaP of sludge biochar decreased with the increase of pyrolysis temperature 300–600℃.The TEQBaP of sludge biochar was the minimum at 600℃(0.9781 mg·kg−1)and the TEQBaP of sludge biochar reached maximum at 700℃(109.7608 mg·kg−1).The 3-ring PAHs contributed the main TEQBaP for rice straw biochar at 300℃and 5-ring PAHs caused the main TEQBaP for sewage sludge and rice straw biochar at other temperatures.Both the content of PAHs and toxicity of sewage sludge and rice straw biochar were the lowest at 600℃.Therefore,considering the content and toxicity of PAHs,600℃was the recommended t
作者
刘丽
范世锁
张锡涛
顾凯业
LIU Li;FAN Shisuo;ZHANG Xitao;GU Kaiye(School of Physics and Electronic Engineering,Fuyang Normal University,Fuyang 236037,China;School of Resources and Environment,Anhui Agricultural University,Hefei 230036,China)
出处
《生态环境学报》
CSCD
北大核心
2020年第9期1874-1882,共9页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(51809001)
安徽省高等学校重点项目(KJ2018A0125,KJ2018A0347)。
关键词
污泥生物炭
秸秆生物炭
多环芳烃
热解温度
毒性当量
sewage sludge biochar
rice straw biochar
polycyclic aromatic hydrocarbons
pyrolysis temperature
toxic equivalent factor
