干法烟气脱硫副产物中汞的形态分布

通过分析干法烟气脱硫副产物中不同形态汞的含量,研究干法脱硫灰中汞的环境稳定性. 利用逐级化学提取法,分析了锅炉底灰、锅炉飞灰、脱硫塔底灰和除尘器灰中水溶态、酸溶态、过氧化氢溶态及王水溶残渣态汞的含量,研究了不同形态汞含量的变化规律. 结果表明,锅炉底灰、锅炉飞灰、脱硫塔底灰和除尘器灰中w（总汞）分别为0.23,0.36,0.46和1.22 mg/kg,且随着脱硫除尘时间的延长w（总汞）呈增加的趋势,其中,以氯化物、硝酸盐和硫酸盐存在的水溶态汞变化明显,除尘器灰中w（水溶态汞）高达0.72 mg/kg. 分析认为,干法烟气脱硫灰吸附的大部分汞蒸气转化为可溶性的氯化物、硝酸盐和硫酸盐等,另外还有少量汞以单质状态存在.      

玻璃纤维编织管动态膜生物反应器处理沼渣废液

一种新型的玻璃纤维编织管动态膜生物反应器应用于高黏度、高氨氮和高COD的沼渣废液的处理。该玻璃纤维编织管经过了固化和覆膜的组合改性,膜组件采用平板化的栅式构型。研究表明:组合改性方式分别为1∶4+1∶50和1∶2+1∶50时的膜组件的稳定通量分别为5.45 L/(m2.h)和6.50 L/(m2.h);同时膜组件的清洗效果良好,再次运行仍能够稳定,通量为5.35 L/(m2.h)。而且出水比较澄清,没有臭味,养分也得到了有效保留。此外,改性后的玻纤编织管估算价格约为93.2元/m2,低于传统有机膜。     

Allelochemicals of the invasive neophyte Polygonum cuspidatum Sieb. & Zucc. (Polygonaceae)

Polygonum cuspidatum Sieb. and Zucc., a traditional Chinese medicine is now a wide-spread invasive neophyte in Europe and America. The novel weapon hypothesis states that some invasive weed species owe part of their success as invaders to allelopathy mediated by some allelochemicals. Previous HPLC/UV/ESI-MS analysis showed that the constituents of the roots of P. cuspidatum from China were obviously different from the species collected in Switzerland (present as an invasive neophyte) with respect to piceatannol glucoside, resveratroloside and some proanthocyanidin. This work isolated these special constituents from the invasive plant and studied their allelopathy effect, as well as the related structures by the seedling and growing model of Lepidium sativum (garden cress, Brassicaceae). The results revealed that stilbenes as piceatannol glucoside, resveratroloside and proanthocyanidins as catechin, epicatechin from this plant were comparatively stronger allelochemicals than the reported allelochemical (−)-catechin, which may partly explain the invasive behavior of this plant in Europe.     

复合型人工湿地模型对污水厂尾水的深度净化效果

采用由一级垂直流湿地、连续的4级沉水植物氧化塘和二级垂直流湿地组成的复合型人工湿地处理小城镇污水处理厂尾水。结果表明,在0.13 m3.m-2.d-1水力负荷条件下,模型出水仅ρ(CODCr)和ρ(氨氮)(以NH4+-N计)达到地表Ⅲ类水标准(GB 3838—2002);但当进水ρ(TP)达到《城镇污水处理厂污染物排放标准》(GB18918—2002)一级B标准时,出水ρ(TP)亦达到地表Ⅲ类水标准。当二级垂直流湿地水力负荷调整为0.06 m3.m-2.d-1时,出水ρ(TP)和ρ(TN)最终都达到地表Ⅲ类水标准。认为水体中TN主要通过一级垂直流湿地的过滤吸附和二级垂直流湿地的反硝化作用去除,而TP则主要以一级垂直流湿地中石灰石的吸附沉降方式来去除。     

动载下石灰岩能耗指标影响因素研究*

为研究石灰岩在动载破坏过程中的能量耗散,基于Φ50 mm的霍普金森压杆系统,对石灰岩开展三轴动静加载冲击试验,深入分析入射能、反射能、透射能、耗散能、能耗率与轴压、围压、应变率（冲击气压）之间的关系,并借助灰色关联理论分析石灰岩围压、应变率、纵波波速与能耗特征的关联。研究结果表明:入射能和耗散能均与应变率呈正向增长趋势,且耗散能应变率相关性更强;能耗率与围压呈反向增长趋势,低围压条件有利于石灰岩的破碎;能耗程度与冲击气压、围压、纵波波速的关联度分别为0.729 9,0.705 4,0.581 5,围压和冲击气压的灰色关联度大于0.6,因此围压和冲击气压对石灰岩能量耗散特征有显著影响。研究结果对于喀斯特地貌石灰岩爆破施工具有重要的参考价值。     

气升循环分体式膜生物反应器再生回用厕所污水的研究

研究了分体浸没式膜生物反应器及其应用于厕所污水的再生回用.试验结果表明,在人水浓度COD440～970mg/L、BOD₅ 307～612mg/L、NH₃-N59～111mg/L的情况下,出水水质稳定,平均COD＜47mg/L、BOD₅＜8.5mg/L、NH₃-N＜20mg/L,处理水质达到建设部颁布的生活杂用水回用标准.研究了动力学参数污泥负荷、容积负荷和HRT对出水COD的影响,确定本试验较佳的污泥负荷和容积负荷分别为0.1kg/(kg·d)和1kg/(m³·d),HRT为7～8h.本文对污泥浓度、温度和产水时间与间歇时间比对膜通量的影响进行了测定与探讨.     

出水水头对自生生物动态膜过滤性能的影响

增加出水水头不利于自生生物动态膜(SFDM)的恢复.随着恢复期出水水头的增加,SFDM的稳定出水通量逐渐达到一个极限通量,约为35L·(m²·h)^-1.继续增大出水水头,稳定出水通量甚至有降低的趋势在相同的出水通量下,动态膜的稳定运行时间随着恢复期出水水头的增加而显著降低.当恢复期出水水头为0.5cm时,稳定运行的时间＞10d,当恢复期出水水头为10cm时,稳定运行时间＜5h.研究了产生上述现象的原因,并提出使每个过滤周期从出水水头为0处开始的操作策略.     

河道综合治理后城市水体沉积物中微塑料污染特征研究 ——以汾河太原城区段为例

以先后经过3期综合整治工程(包括截污纳管 、湿地营建 、滨河景观建设等)的汾河太原城区段为研究对象,对其沉积物中微塑料进行了研究.结果表明:汾河太原城区段沉积物中微塑料丰度为108～732个/kg,上游未经河道治理的采样点丰度最高,河道综合治理后微塑料丰度明显下降;白色(35％)在所有微塑料颜色中占比(数量占比,下同)...     

Synthesis and applications of carbon quantum dots derived from biomass waste: a review

Environmental Chemistry Letters - In the context of the circular economy and decreasing earth resources, waste should be converted into value-added materials such as carbon quantum dots, which are...     

Enhancement of extracellular Cr(VI) reduction for anammox recovery using hydrazine: performance,pathways, and mechanism

● N₂H₄ addition enhanced and recovered anammox performance under Cr(VI) stress. ● N₂H₄ accelerated electron transfer of Cr(VI) reduction for detoxification. ● N₂H₄ enhanced anammox metabolism for activity recovery from Cr(VI) inhibition. ● Extracellular Cr(VI) reduction to less toxic Cr(III) was the dominant mechanism. The hexavalent chromium (Cr(VI)) would frequently impose inhibition to anaerobic ammonium oxidation (anammox) process, hindering the efficiency of nitrogen removal in wastewater treatment. Hydrazine (N₂H₄), which is an intermediate product of anammox, participates in intracellular metabolism and extracellular Cr(VI) reduction. However, the roles of N₂H₄-induced intracellular metabolism and extracellular reduction in nitrogen removal under Cr(VI) stress remain unclear. The addition of 3.67 mg/L of N₂H₄ increased the anammox activity by 17%. As an intermediate, N₂H₄ enhanced anammox metabolism by increasing the heme c content and electron transfer system activity. As a reductant, N₂H₄ accelerated the reduction of c-Cyts-mediated extracellular Cr(VI) to the less toxic Cr(III). Extracellular Cr(III) accounts for 74% of the total Cr in a Cr(VI)-stressed anammox consortia. These findings highlight that N₂H₄-induced extracellular Cr(VI) reduction is the dominant mechanism for the survival of anammox consortia. We also found that N₂H₄ increased the production of extracellular polymeric substances to sequester excessive Cr(VI) and produced Cr(III). Taken together, the study findings suggest a potential strategy for enhancing nitrogen removal from ammonium-rich wastewater contaminated with Cr(VI).