In -situ synchronous carbonation and self -activation of biochar/geopolymer composite membrane: Enhanced catalyst for oxidative degradation of tetracycline in water
In -situ synchronous carbonation and self -activation of biochar/geopolymer composite membrane: Enhanced catalyst for oxidative degradation of tetracycline in water
复制标题
生物炭/地质聚合物复合膜的原位同步碳酸化和自活化：水中四环素氧化降解的增强催化剂
DOI：
10.1016/j.cej.2020.125528
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发表时间：
2020-10-01
影响因子：
15.1
通讯作者：
Cui, Xuemin
中科院分区：
文献类型：
--
作者：
Huang, Jiaqi;Li, Zhili;Cui, Xuemin
以两种可持续材料为原料，采用原位同步碳化和自活化工艺制备了生物炭/地聚合物复合膜(BC/GM)。整体式地聚合物膜(GM)不仅作为多孔载体，实现了生物炭(BC)的良好分散和回收，而且在木质素前体碳化过程中也为生物炭的就地活化提供了坚实的基础。制得的BC/GM具有层次化的多孔结构(分别在3.54和16.53 nm处呈现双峰孔径分布)，具有较大的比表面积(37.46×m~2/g，是BC的28倍)，含有丰富的官能团(C单键、C双键和双键C单键等)。较高的石墨化程度(ID/IG=0.81)，在分解过氧化氢生成·OH自由基降解四环素(TC)方面表现出较高的活性。0.15 g BC/GM(1g H_2O_2，pH值5.0，60℃，5h)对总胆固醇(50 mg/L，100g/L)的去除效果接近100%。在5次循环中表现出良好的稳定性和可重用性。EPR、XPS、FTIR和拉曼光谱分析表明，BC中的酚羟基、酮、苯二酚和缺陷结构有助于将电子转移到H_2O_2中生成·OH，而BC中具有多孔结构和较大比表面积的石墨化碳提供了催化剂与TC分子之间的紧密接触，从而提高了催化剂的电子导电性，抑制了氧化还原反应中·OH自由基的衰减，最终实现了TC通过开环反应、异构化、脱甲基、脱胺和脱水反应有效地降解TC为CO2、H2O和其他无机化合物。
A new biochar/geopolymer composite membrane (BC/GM) was prepared by anin-situsynchronous carbonation and self-activation process from two sustainable materials. The monolithic geopolymer membrane (GM) served not only as a porous support, achieving good dispersion and retrieve of biochar (BC), but also as a solid base forin-situactivating BC during carbonization of lignin precursor. The obtained BC/GM contained a hierarchically porous structure (exhibiting a bi-modal pore size distribution at 3.54 and 16.53 nm, respectively), having a large specific surface area (37.46 m2/g, 28 times of BC), containing rich functional groups (Csingle bondOH, Cdouble bondO and Odouble bondCsingle bondO,etc.) and a high degree of graphitization (evidenced by a lower value of ID/IG= 0.81) which exhibited a high activity in decomposing H2O2to generate ·OH radicals for degradation of tetracycline (TC). Nearly 100% of TC (50 mg/L, 100 mL) was removed by 0.15 g BC/GM (1 mL H2O2, pH 5.0, 60 °C, 5 h). It also showed a good stability and reusability during 5 repeated cycling. EPR, XPS, FTIR and Raman analysis suggested the phenolic-OH, ketone, quinone moieties and defect structures in BC contributed to the generation of ·OH through transferring electrons to H2O2, while the graphitized carbon in BC with porous structure and large surface area provided intimate contact between catalyst and TC molecules that accordingly enhanced the electron conductivity and suppressed the decay of ·OH radicals during redox reaction, which eventually realized the efficient degradation of TC into CO2, H2O, and other inorganic compounds through ring-opening reaction, isomerization, demethylation, deamination, and dehydration reaction.