餐饮废水的化学处理方法研究

以聚硅酸铝为混凝剂,用化学法絮凝处理餐饮废水。考查了酸度、混凝剂加入量、搅拌速度、搅拌时间、沉降时间对CODCr去除率的影响。结果表明酸度在pH9～11范围内,每100mL污水中聚硅酸铝加入量为02mL,搅拌速度为45r/min,搅拌15s,沉降15min后,测上清液的化学耗氧量,CODCr去除率可达88%左右。该方法效果好、工艺简单、易于操作管理,有实际应用价值。     

Controllable synthesis Fe3O4@POHABA core-shell nanostructure as high-performance recyclable bifunctional magnetic antimicrobial agent

We demonstrated a method to form magnetic antimicrobial POHABA (poly-N,N′-[(4,5-dihydroxy-1,2-phenylene)bis(methylene)]bisacrylamide)-based core-shell nanostructure by free-radical polymerization of OHABA on the Fe₃O₄ core surface. The magnetic antimicrobial agent Fe₃O₄@POHABA can be used in domestic water treatment against bacterial pathogens. The thickness of POHABA shell could be controlled from 10.4 ± 1.2 to 56.3 ± 11.7 nm by the dosage of OHABA. The results of antimicrobial-activity test indicated that POHABA-based core-shell nanostructure had broad-spectrum inhibitory against Gram-negative, Gram-positive bacteria and fungi. The minimum inhibitory concentration (MIC) values of Fe₃O₄@POHABA nanostructure against Escherichia coli and Bacillus subtilis were both 0.4 mg/mL. Fe₃O₄@POHABA nanostructures responded to a permanent magnet and were easily recycled. Fe₃O₄@POHABA nanoparticles retained 100% antimicrobial efficiency for both Gram-negative and Gram-positive bacteria throughout eight recycle procedures.

     

厦门冬春季大气VOCs的污染特征及臭氧生成潜势

2014年1~4月在厦门市城区和郊区开展冬春季节大气样品的采集,采用大气预浓缩系统与GC/MS联用技术定量了48种大气挥发性有机物(VOCs),对比分析了冬春季城区和郊区大气VOCs的污染特征,并利用最大增量反应活性(MIR)估算了大气VOCs的臭氧生成潜势(OFP).结果表明,冬季厦门城区和郊区大气中VOCs的平均体积分数分别为11.13×10-9和7.17×10-9,春季厦门城区和郊区大气中VOCs的平均体积分数分别为24.88×10-9和11.27×10-9,且均表现为烷烃芳香烃烯烃.通过B/T值探讨城区和郊区VOCs的来源发现,机动车和溶剂挥发是城区VOCs的主要来源,郊区VOCs除了局地源的贡献外,还受到外来污染物扩散传输的影响.城、郊区的主要VOCs包括丙烯、正丁烷、异丁烷、正戊烷、异戊烷、正己烷、苯、甲苯、乙苯和间对二甲苯,这10种组分对两地VOCs的贡献表现为春季(城区和郊区分别为62.83%和53.74%)高于冬季(城区和郊区分别为61.57%和45.83%).城、郊区VOCs的臭氧生成潜势分析显示,芳香烃的相对贡献率最大,其次是烯烃,烷烃最小.C3、C4类烯烃和苯系物是厦门城区和郊区活性较高的物种,对臭氧的贡献较大.比较观测期间城区和郊区VOCs的平均MIR值可知,郊区VOCs的活性高于城区.     

巴伊盆地平原区地下水水化学特征及污染源识别

为探明新疆巴伊盆地平原区地下水水化学特征及形成机制并解析污染源,综合运用数理统计、图解法和PCA-APCS-MLR模型等方法,对2022年8月采集的4组泉水样、 20组潜水样和11组承压水样的测试结果进行分析.结果表明,研究区地下水化学类型复杂多样,泉水以HCO₃·SO₄-Na·Ca型地下水为主,潜水以HCO₃·SO₄-Na·Ca型和HCO₃·SO₄-Ca型地下水为主,承压水水化学类型主要为HCO₃·SO₄-Na·Ca型和HCO₃·Cl·SO₄-Na·Ca型;未利用地承压水水化学类型单一(Cl·SO₄-Na·Ca型),耕地及城乡居民用地承压水水化学类型复杂,表明地下水受到人类活动影响;地下水演化过程主要受到水岩相互作用与阳离子交换作用的影响,从泉水至潜水至承压水阳离子交换作用逐渐增强,石膏及硬石膏的风化溶解作用逐渐减弱、岩盐的风化溶解作用逐渐加强;...     

气候变化背景下人类活动对承德接坝区植被净初级生产力的影响

承德接坝区位于农牧过渡区,对气候变化和人类活动极为敏感.以植被净初级生产力(NPP)作为评价指标,基于Thornthwaite Memorial模型计算潜在NPP和MODIS NPP遥感影像获取实际NPP数据,利用潜在NPP与实际NPP间的差值衡量人类活动作用下NPP的大小,运用Slope趋势和变异系数法分析实际NPP、潜在NPP和人类活动作用下NPP的变化趋势及稳定性分布,并采用相关系数法分析实际NPP与年降水量和年均气温间的相关性,最终量化气候变化和人类活动对该区域植被变化的影响.结果表明,潜在NPP自西北向东南递增,其变化趋势和稳定性均为自西向东递增.实际NPP与年降水量和年均气温呈正相关区域面积占比分别是99.87%和91.66%.该区域99.85%的植被得到改善且变化稳定,主要是由气候因素和人类活动共同主导(99.71%),而植被退化完全是由人为因素所导致(0.15%).     

环境因素对文物的影响及文物考古环境保护问题探讨

文章在分析大气、水、辐射、地下水等环境因素对文物的影响和文物考古对环境影响的基础上,从田野考古的环境保护措施、文物及遗址的保护与生态环境的改善、加强污染防治,保证环境质量、环保部门与文物部门合作等方面提出文物考古及保护的环境保护措施建议。     

区域规划环评中生态系统服务功能影响评价方法初探研究

生态系统服务功能是维系区域生态系统安全的重要保障,从生态系统服务功能角度评价区域规划对生态系统的影响具有重要意义。目前在规划环评中应用生态系统服务功能评价的案例仍然较少,本文基于目标导向性影响评价理念,构建生态系统服务功能影响指标体系,以及基于RS与GIS技术的空间评价方法,旨在探索建立一套适用于区域尺度规划环境影响评价的可行的生态系统服务功能影响评价模式。针对区域主要的生态系统服务功能类型,选择能够准确衡量功能强弱且对人类干扰敏感的因子作为主要评价指标．通过指标的变化趋势和规划建设空间分析,评价规划实施对区域主要生态系统服务功能造成的影响,根据评价结果提出相应的避让、减缓、补偿、优化等对策措施,保障区域生态系统服务功能不降低。     

京杭运河常州段氮形态的时空分布特征研究

对京杭运河常州段8个研究点位水体中的氮形态（TN、NH4＋-N、NO2--N和NO3--N）和环境因子（pH、T和DO）进行了连续9个月的动态监测,全面研究了各氮形态的随时间和空间的动态变化规律,并对各氮形态及环境因子进行了相关性分析。常州段水体月平均NH4＋-N变化范围为（0.589±0.351）～（3.148±1.178）mg.L-1,TN变化范围为（3.373±1.379）～（7.373±2.307）mg.L-1,枯水期到丰水期各氮形态整体表现出波动性下降趋势,其中出境断面NH4＋-N下降趋势平稳,NO3--N则是主导出境断面TN含量的主要形态。各点位NH4＋-N的平均浓度范围为（1.202±0.492）～（2.813±1.566）mg.L-1,TN范围为（3.520±0.504）～（8.349±3.679）mg.L-1,各形态氮含量基本呈现出上游段（S）〈新运河（G）〈老运河（L）〈下游（X）的空间分布特征,其中下游段存在一个重要的氮素上升突变段,NO3--N是对TN的贡献率（43.8%～57.4%）最大的无机态氮,其次是NH4＋-N、ON、NO2--N,其中有机氮对TN的贡献率（13.3%）则以老河段最高。NH4＋-N和NO3--N、TN、pH相关系数分别为0.397＊＊、0.932＊＊、0.261＊,与DO相关系数为-0.344＊＊,陆源输入及DO不足是京杭运河常州段氮污染严重的重要原因。     

Nitrous oxide emissions from black soils with different pH

N₂O fluxes as a function of incubation time from soil with different available N contents and pH were determined. Cumulative carbon dioxide (CO₂) emissions were measured to indicate soil respiration. A 144-hr incubation experiment was conducted in a slightly acidic agricultural soil (pH_H2O 5.33) after the pH was adjusted to four different values (3.65, 5.00, 6.90 and 8.55). The experiments consisted of a control without added N, and with NH₄⁺-N and NO₃^--N fertilization. The results showed that soil pH contributed significantly to N₂O flux from the soils. There were higher N₂O emissions in the period 0-12 hr in the four pH treatments, especially those enhanced with N-fertilization. The cumulative N₂O-N emission reached a maximum at pH 8.55 and was stimulated by NO₃^--N fertilization (70.4 μg/kg). The minimum emissions appeared at pH 3.65 and were not stimulated by NO₃^--N or NH₄⁺-N fertilization. Soil respiration increased significantly due to N-fertilization. Soil respiration increased positively with soil pH (R² = 0.98, P < 0.01). The lowest CO₂-C emission (30.2 mg/kg) was presented in pH 3.65 soils without N-fertilization. The highest CO₂-C emissions appeared in the pH 8.55 soils for NH₄⁺-N fertilization (199 mg/kg). These findings suggested that N₂O emissions and soil respiration were significantly influenced by low pH, which strongly inhibits soil microbial nitrification and denitrification activities. The content of NO₃^--N in soil significantly and positively affected the N₂O emissions through denitrification.