循环经济发展战略下的企业决策行为研究——以天津滨海新区为例

在循环经济发展战略下,企业呈现出不同的行为模式,选择差异性目标和决策成本构成了企业的决策过程.转变经济发展方式的要求强化了企业所面对的市场竞争,而企业发展循环经济是具有内在动力机制的市场化行为.     

焦化废水泡沫分离液的Fenton催化氧化预处理

以焦化废水处理过程产生的泡沫分离液为研究对象,对其进行Fenton催化氧化处理实验,考察H₂O₂用量、Fe²⁺浓度、pH和反应时间4个因素对处理效果的影响,并结合GC/MS方法比较处理前后泡沫分离液中有机物的种类及其生物降解性的变化。结果表明,采用［H₂O₂］=100 mmol/L、［Fe²⁺］=100 mg/L、pH=3、反应时间为30 min的Fenton催化氧化反应条件,可以使分离液的COD去除率达到68%以上;经Fenton处理后,分离液的B/C值由0.12提高至0.38,生物降解性明显改善;通过GC/MS的分析,基本明确分离液中含有的有机物主要为酚、胺、腈、酯类有机物及喹啉、吡啶等杂环化合物,大多数属于难降解且生物毒性较强的有机物。针对这些复杂组分共存的泡沫分离液,利用Fenton试剂较强的氧化能力能够将其含有的有毒/难降解有机物转化为低毒或无毒的小分子有机物,为其后续的生物处理创造良好的条件。     

TiO_2/NiFe_2O_4磁性纳米光催化剂的制备及其光催化性能研究

先用水热法制备了纳米级NiFe2O4磁核,然后采用均匀沉淀法在NiFe2O4磁核表面包覆TiO2,制备了一种新型磁性纳米光催化剂TiO2/NiFe2O4。通过实验确定了制备TiO2/NiFe2O4的最佳Ti/Ni(摩尔比)为30/1,用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外—可见(UV—Vis)漫反射、热重—差示扫描量热分析(TG—DSC)、磁力学测试等手段对其进行了表征。以甲基橙的水溶液为模拟污染物,评价了TiO2/NiFe2O4的光催化性能,在光照2h后,甲基橙的脱色率可达98.5%。研究结果表明,TiO2/NiFe2O4是一种可重复使用的高效光催化剂。     

Carbonaceous matter and PBDEs on indoor/outdoor glass window surfaces in Guangzhou and Hong Kong,South China

Organic films, collected from indoor and outdoor window surfaces in Guangzhou and Hong Kong of South China, were analyzed to quantify their organic carbon (OC), elemental carbon (EC), and polybrominated diphenyl ethers (PBDEs) content. The highest concentrations of OC, EC, and BDE-209 were found in Guangzhou with values of 10 000 μg m^?2, 2200 μg m^?2, and 4000 ng m^?2, respectively, and the highest concentration of Σ₇PBDE (sum of BDE-28, -47, -99, -100, -153, -154 and -183) was found in Hong Kong with a value of 25 ng m^?2. In most cases, the concentrations of PBDEs were higher in the exterior films than those in the interior films with BDE-209 as the predominant congener in both cities, suggesting that PBDEs mainly come from ambient environment, and deca-BDE accounts for major PBDE consumption. The growth rates of organic film on window surfaces were fast at the beginning, and reached a consistent level afterwards. The evolution rates ranged from 2.6 to 11 nm day^?1 for “bulk film”, while from 0.06 to 0.92 nm day^?1 for “pure film”. The concentrations of PBDEs on the window surfaces did not increase with the growth time, suggesting that the window surface may provide a good place for photo-degradation of PBDEs.     

好氧膜-生物反应器中微滤膜选择的实验研究

用扫描电镜表面观察和全自动压汞仪测定了2种亲水化改性PVDF微滤膜的平均孔径、孔隙率等基本性能参数。对2种膜的纯水通量,及其平板膜组件在好氧膜生物反应器内污染过程进行分析。结果显示,2种膜污染过程均呈现先缓慢后快速的"二阶段"趋势,第二阶段是膜污染的主导阶段。尽管平均孔径小、孔隙率高的膜本身阻力大、纯水通量低,但其污染速率较低,物理及化学清洗恢复率较高。膜孔径及孔隙率指标是影响其在MBR中运行的污染速率的主要因素,平均孔径小、孔隙率高的膜抗污染能力强。     

氧化/吸附/混凝协同工艺处理焦化废水生物处理出水的过程及效果分析

针对焦化废水生物处理出水中继续存在多种有机污染物而影响达标及存在安全隐患的现状,基于废水中有机物的物理化学特性,构建了氧化/吸附/混凝的深度处理过程。在NaC lO投加量为40 mg/L,AC投加量为500 mg/L,PFS投加量为300 mg/L,反应时间为0.5 h,以及pH为7.0的最佳条件下,先氧化后吸附混凝,该过程可以实现COD去除率为75%以上,色度去除率80%以上,处理后的水样其COD值与色度值分别下降到60 mg/L及20倍以下;通过GC/MS方法分析处理前后水样中的有机物组分,发现水样中大部分单环芳香族化合物和多环芳香族化合物,部分含氮杂环化学物、有机氯化物以及溴化物被去除,但是,长链烷烃和部分芳香烃继续保留。研究结果证明了氧化/吸附/混凝协同工艺的效果与焦化废水生物出水中有机污染物的分子结构、存在形态形成构效关系,催化作用与氧化作用的协同是获得高效去除率的关键。     

序批式反应器处理垃圾渗滤液的污泥颗粒化及污染物去除性能研究

应用序批式反应器(SBR)处理垃圾渗滤液,以絮状活性污泥为接种污泥,经过37 d的运行,反应器内出现小粒径颗粒污泥。第50 d,反应器中污泥完全颗粒化。稳定运行期间,反应器内污泥的平均粒径为0.7 mm;SVI5min一直维持在较低的水平(27~47 mL/g);MLSS基本稳定在3 700~4 500 mg/L;当COD和氨氮的平均进水浓度为2 150 mg/L和312 mg/L时,平均出水浓度分别为540 mg/L和35 mg/L,去除率分别为75%和89%。     

板框压滤机内酒精污泥过滤脱水特性

采用螺杆泵输送和板框过滤机压滤的方法对酒精污泥进行机械脱水,研究了絮凝剂(聚丙烯酰胺PAM)添加量、污泥的进口湿含量、螺杆泵转速、过滤介质和过滤时间对污泥过滤特性的影响,并对滤饼吹气压榨进一步脱水。实验表明,在PAM添加量wPAM=3 kg/(t干污泥),污泥的进口湿含量x0=95%,螺杆泵转速n=180 r/min,过滤时间t=2.5 h并进行吹气压榨可将污泥的湿含量降至69.91%。     

Cesium and strontium sorption by selected tropical and subtropical soils around nuclear facilities

The dynamics of Cs and Sr sorption by soils, especially in the subtropics and tropics, as influenced by soil components are not fully understood. The rates and capacities of Cs and Sr sorption by selected subtropical and tropical soils in Taiwan were investigated to facilitate our understanding of the transformation and dynamics of Cs and Sr in soils developed under highly weathering intensity. The Langmuir isotherms and kinetic rates of Cs and Sr sorption on the Ap1 and Bt1 horizons of the Long-Tan (Lt) and the A and Bt1 horizons of the Kuan-Shan (Kt), Mao-Lin (Tml) and Chi-Lo (Cl) soils were selected for this study. Air-dried soil (<2 mm) samples were reacted with of 7.5 × 10⁻⁵ to 1.88 × 10⁻³ M of CsCl (pH 4.0) or 1.14 × 10⁻⁴ to 2.85 × 10⁻³ M of SrCl₂ (pH 4.0) solutions at 25 °C. The sorption maximum capacity (q_m) of Cs by the Ap1 and Bt1 horizons of the Lt soil (62.24 and 70.70 mmol Cs kg⁻¹ soil) were significantly (p < 0.05) higher than those by the A and Bt1 horizons of the Kt and Cl soils (26.46 and 27.49 mmol Cs kg⁻¹ soil in Kt soil and 34.83 and 29.96 mmol Cs kg⁻¹ soil in Cl soil, respectively), however, the sorption maximum capacity values of the Lt and Tml soils did not show significant differences. The amounts of pyrophosphate extractable Fe (Fe_p) were correlated significantly with the Cs and Sr sorption capacities (for Cs sorption, r² = 0.97, p < 1.0 × 10⁻⁴; for Sr sorption, r² = 0.82, p < 2.0 × 10⁻³). The partition coefficient of radiocesium sorbed on soil showed the following order: Cl soil ? Kt soil > Tml soil > Lt soil. It was due to clay minerals. The second-order kinetic model was applied to the Cs and Sr sorption data. The rate constant of Cs or Sr sorption on the four soils was substantiality increased with increasing temperature. This is attributable to the availability of more energy for bond breaking and bond formation brought about by the higher temperatures. The rate constant of Cs sorption at 308 K was 1.39-2.09 times higher than that at 278 K in the four soils. The activation energy of Cs and Sr sorbed by the four soils ranged from 7.2 to 16.7 kJ mol⁻¹ and from 15.2 to 22.4 kJ mol⁻¹, respectively. Therefore, the limiting step of the Cs⁺ or Sr²⁺ sorption on the soils was diffusion-controlled processes. The reactive components, which are significantly correlated with the Langmuir sorption maxima of Cs and Sr by these soils, substantially influenced their kinetic rates of Cs and Sr sorption. The data indicate that among components of the subtropical and tropical soils studied, short-range ordered sesquioxides especially Al- and Fe-oxides complexed with organics play important roles in influencing their capacity and dynamics of Cs and Sr sorption.     

Bioremediation of strontium (Sr) contaminated aquifer quartz sand based on carbonate precipitation induced by Sr resistant Halomonas sp

Contamination of aquifers or sediments by radioactive strontium (⁹⁰Sr) is a significant environmental problem. In the present study, microbially induced calcite precipitation (MICP) was evaluated for its potential to remediate strontium from aquifer quartz sand. A Sr resistant urease producing Halomonas sp. was characterized for its potential role in bioremediation. The bacterial strain removed 80% of Sr from soluble-exchangeable fraction of aquifer quartz sand. X-ray diffraction detected calcite, vaterite and aragonite along with calcite-strontianite (SrCO₃) solid solution in bioremediated sample with indications that Sr was incorporated into the calcite. Scanning electron micrography coupled with energy-dispersive X-ray further confirmed MICP process in remediation. The study showed that MICP sequesters soluble strontium as biominerals and could play an important role in strontium bioremediation from both ecological and greener point of view.