Enhanced heterogeneous Fenton-like activity by Cu-doped BiFeO<Subscript>3</Subscript> perovskite for degradation of organic pollutants

Heterogeneous Fenton-like reaction has been extensively investigated to eliminate refractory organic contaminants in wastewater, but it usually shows low catalytic performance due to difficulty in reduction from Fe(III) to Fe(II). In this study, enhanced catalytic efficiency was obtained by employing Cu-doped BiFeO₃ as heterogeneous Fenton-like catalysts, which exhibited higher catalytic performance toward the activation of H₂O₂ for phenol degradation than un-doped BiFeO₃. BiFe_0.8Cu_0.2O₃ displayed the best performance, which yielded 91% removal of phenol (10 mg L^–1) in 120 min. The pseudo first-order kinetic rate constant of phenol degradation in BiFe_0.8Cu_0.2O₃ catalyzed heterogeneous Fenton-like reaction was 5 times higher than those of traditional heterogeneous Fenton-like catalysts, such as Fe₃O₄ and goethite. The phenol degradation efficiency could still reach 83% after 4 cycles, which implied the good stability of BiFe_0.8Cu_0.2O₃. The high catalytic activity of BiFe_0.8Cu_0.2O₃ was attributed to the fact that the doping Cu into BiFeO₃ could promote the generation of Fe(II) in the catalyst and then facilitate the activation of H₂O₂ to degrade the organic pollutants.

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内爆炸下肋环型球面钢网壳的泄爆阈值研究

利用有限元软件LS-DYNA建立包含TNT炸药、网壳杆件、梁、柱、地面、围护结构(墙面和屋面)以及连接构件在内的单层肋环型球壳在内部中心爆炸下的数值模型。基于该模型,计算分析TNT炸药量和连接构件抗拉刚度的变化对墙面和屋面破坏模式的影响。将墙面和屋面的破坏模式进行归纳分类,通过提取围护结构表面有限测点的冲击波压力,得到不同破坏模式下结构的极限冲击波超压值ΔPlimf(泄爆阈值)。研究结果表明:连接构件抗拉刚度和TNT炸药量对墙面和屋面的破坏有较大影响,TNT炸药量一定时,连接构件抗拉刚度越大,围护结构破坏程度越低;基于墙面和屋面的破坏模式所建立的泄爆阈值与连接构件抗拉刚度的变化范围可为工程泄爆设计提供有效参考。     

Release of elements from municipal solid waste incineration fly ash

The element-release behavior of municipal solid waste incineration fly ash was explored through leaching test with continuous set-point pH (pH_stat test) and serial single reaction cell (SSRC) tests. First, the relationship between element release and acid neutralizing capacity (ANC) consumption was examined with a pH_stat test. Four types of release behaviors were identified which are characteristic for different elements: (1) release curves that were almost linear with ANC consumption (Ca, Zn, and Cd); (2) release that was significantly faster than ANC (Na, K, and Cl); (3) curves that featured a strong increase with ANC consumption, after a transient release, followed by an almost equal decrease (Si and S); and (4) release that is strongly retarded compared with ANC consumption (Cr, Cu, and Pb). In the SSRC system, it the existence of a pH front and a wash-out phenomenon is demonstrated. Combining the results from the SSRC test with the kinetic analysis of the ANC system in the pH_stat test, it was inferred that less than one-third of the ANC measured from a batch pH titration plays a neutralization role in a field situation. The methodologies described may provide a powerful set of tools for systematic evaluation of element release from solid wastes.     

气体钻井突发性井壁失稳动力演化机理及试验研究

从致密砂岩损伤破坏的角度出发,综合考虑致密砂岩的物理力学性质、地应力、裂缝圈闭高压等因素,在分析孔隙压力、地应力、裂缝圈闭高压在突发性井壁失稳过程中所起的作用基础上,将气体钻井突发性井壁失稳具有强烈时间效应的动态力学过程分为孕育、突变、井筒运移和终止4个阶段。对裂缝圈闭高压、地应力作用下致密砂岩的加速损伤演化引起的突发性井壁失稳机理进行了阐述,裂缝圈闭高压是突发性井壁失稳的主要动力源,地应力对突发性井壁失稳起辅助作用。通过模拟实验表明,受地应力破坏后的致密砂岩岩体在有裂缝情况下,卸压初始时刻释放的能量是无裂缝时的5~10倍,且该能量与动力学失稳密切相关。     

中外垃圾土体渗透系数试验对比分析

从试验数据、试验方法 2个方面总结归纳了关于现有垃圾填埋场渗透系数的国内外试验,并且通过对比国内外渗透系数的一系列试验成果,分析了国内外渗透系数试验在基础数据、试验方法多样性方面的优劣。以此为基点,对未来国内岩土工程发展方向提出了建议。     

Effect of thermal pretreatment on the physical and chemical properties of municipal biomass waste

The effects of thermal pretreatment on the physical and chemical properties of three typical municipal biomass wastes (MBWs), kitchen waste (KW), vegetable/fruit residue (VFR), and waste activated sludge (WAS) were investigated. The results show that thermal pretreatment at 175 °C/60 min significantly decreases viscosity, improves the MBW dewatering performance, as well as increases soluble chemical oxygen demand, soluble sugar, soluble protein, and especially organic compounds with molecular weights >10 kDa. For KW, VFR and WAS, 59.7%, 58.5% and 25.2% of the organic compounds can be separated in the liquid phase after thermal treatment. WAS achieves a 34.8% methane potential increase and a doubled methane production rate after thermal pretreatment. In contrast, KW and VFR show 7.9% and 11.7% methane decrease because of melanoidin production.     

石化生产装置挥发性有机化合物的泄漏检测

阐述了石化生产装置挥发性有机化合物泄漏检测工作的主要环节,介绍了主要的泄漏检测对象和检测部位,以及对检测人员的要求,给出了从检测仪器的检定和核查、响应因子、检测方法、背景干扰、数据记录等方面确保检测质量的方法.     

发酵法溶剂生产工艺的流程模拟与参数优化

对发酵法溶剂生产的精馏工艺流程采用化工流程模拟软件PROII进行了模拟。将复杂的流程分为醪塔子系统、丁塔子系统和乙丙子系统,采用液体活度系数模型NRTL和非理想物系的CHEMDIST算法,利用Distillation模块、Simple HX模块、Flash模块和Mixer模块分别进行模拟。流程模拟结果与实际运行结果吻合良好。在此基础上,以减少塔釜废液中溶剂含量为优化目标,利用中心组合设计(CCD)与PROII流程模拟相结合,对醪塔的部分操作参数进行了优化。优化后可使废液中溶媒含量减少至0.008%,远低于原工艺数据。     

废聚苯乙烯塑料共焦化过程的生命周期评价

随着我国废塑料资源化利用技术的不断发展,其资源化过程中的环境问题也日益显现。以生命周期评价为研究方法,对废聚苯乙烯共焦化过程的环境影响进行评价。研究结果表明:废聚苯乙烯共焦化过程对酸化、烟尘和粉尘、全球变暖3类环境问题的影响较大,分别占了总影响的34.0%、27.5%和23.3%。从共焦化过程的3个阶段来看,入炉炼焦阶段的环境影响最大,其次是混合颗粒制备阶段和PS颗粒制备阶段,对炼焦阶段环境污染的控制是废塑料共焦化技术发展的关键。     

酸性橙Ⅱ废水催化铁内电解法脱色研究

对催化铁内电解法处理酸性橙Ⅱ废水进行了研究,考察了进水pH、搅拌速率、进水酸性橙Ⅱ浓度、铁铜比、支持电解质浓度、进水温度等因素对脱色效果的影响。在最优反应条件下,酸性橙Ⅱ的去除率大于98％,COD的去除率大于76％。催化铁内电解法对酸性橙Ⅱ的去除非常有效,且有较宽的pH适应范围。