为推进衢州市氮污染的治理,基于人类活动净氮输入模型（NANI）估算了衢州市2003～2022年净氮输入量,分析了NANI时空特征、组分变化原因及影响因素.结果表明:衢州市NANI 20a平均值为12925kg/（km 2 ·a）,时间变化呈现出先增加后降低的趋势,2011年达到峰值15698kg/（km 2 ·a）.各子单元空间表现出一定差异性,空间分布呈现出东高西低的分布,与土地利用状况分布接近.NANI的各组分占比表现为氮肥施用约占27%～41%,食物/饲料净氮输入约占22%～42%,大气氮沉降约占21%～33%,固氮约占7%～11%.NANI的变化在2003～2008年主要受氮肥施用的影响,在2009～2014年主要受食物饲料净氮输入的影响,近年则主要受大气氮沉降影响.减少NANI的主要策略有全面推广新能源汽车的应用;降低农田氮肥施用量逐步调整至农业发达国家平均采用的施肥标准;以满足衢州市本地人口对畜禽产品的基本需求为限,合理调控畜禽养殖规模.实施这些措施后,预计NANI可分别降低约833,893,896kg/（km 2 ·a）,总量降低约2622kg/（km 2 ·a）,达到世界上较低水平.
This paper analyzes the adsorption mechanism of the Permeable Reactive Barrier(PRB)with bamboo charcoal-zeolite mixture to cadmium,as well as its timeliness combining physico-mechanical tests,static batch tests,dynamic column experiments,microscopic characterization analysis,and groundwater flowing numerical simulation.When bamboo charcoals(particle size greater than 0.18mm)and zeolites(particle size greater than 0.5mm)were mixed in a mass fraction of 1∶10 to 3∶10,the bamboo charcoal-zeolite mixtures could not only remove cadmium from groundwater effectively,but also had good permeability and shear strength.The adsorption capacity of the bamboo charcoal-zeolite mixtures for cadmium increased with the growing bamboo charcoal ratio and decreasing particle size.The penetration and depletion time of the PRB column decreased with increasing groundwater flowing rate and column concentration.The removal reactions of cadmium by bamboo charcoal-zeolite mixtures mainly included complexation,chelation,and ion-exchange.At a groundwater cadmium contaminated site with a thicker PRB and slower groundwater flowing rate,the effective operation time of the PRB was longer.
Various flushing solutions that contain hydrophobic organic compounds and surfactants are generated during surfactant-enhanced soil flushing processes. How to effectively remove the target pollutants while minimizing the degradation of surfactants for reuse of the flushing solutions has become a major problem. A series of batch experiments were conducted to investigate the preferential degradation mechanisms of naphthalene by sodium dodecyl sulfate (SDS) as well as the effect of SDS concentration on the degradation efficiency using a competitive kinetic method. In addition, the effects of persulfate (PS) dosage, temperature, and pH on the degradation efficiency of naphthalene were also studied, and a prediction model based on response surface methodology (RSM) was built to optimize the preferential degradation of naphthalene. One-dimensional column flushing experiments were performed to evaluate the feasibility of reusing soil flushing solutions at the predicted PS dosage. Results show that: (i) SDS inhibited naphthalene degradation owing to competitive oxidation and micellar protection, with a decreasing degradation rate constant as SDS concentration increased. However, naphthalene was still degraded by reactive oxygen species (ROS) at a higher rate than SDS, indicating the preferential degradation of naphthalene. When the concentration of SDS increased from 5 to 10 times of critical micelle concentration (CMC; 8.2 mM), the ratio for rate constants of naphthalene to SDS (kNAP/kSDS) decreased significantly from 31.61 to 3.38, illustrating the obvious effect of SDS concentration on preferential degradation of naphthalene; (ii) The formation of single-chambered vesicles with a higher thermodynamic stability was observed at 10 CMC, compared to the spherical micelles formed at 5 CMC. The accessibility of naphthalene to ROS was greatly reduced at 10 CMC, resulting in a significant reduction in kNAP/kSDS value. Moreover, the method in which ROS attacked naphthalene in surfactant micelles varied with SDS concentration, which also impacted the preferential degradation of naphthalene; (iii) Under the optimal PS dosage predicted by the RSM model, a good reusability of SDS was observed in the soil flushing solutions after thermally activated PS oxidation, with a significant reduction on the toxic risk of soil after flushing.
对比了7种高级氧化工艺(电解、臭氧、紫外、电产有效氯、电产过氧化氢、紫外/电产有效氯、紫外/电产过氧化氢)在果蔬清洗消毒中的效果.结果表明,紫外/电产过氧化氢工艺具有最好的杀灭大肠杆菌的能力,在5min内完全杀灭了浓度为7.11log CFU/mL的大肠杆菌,且未出现光复活.该工艺也具有较好的阿特拉津降解能力,在10min内降解率达到93.2％.此外,该工艺还可有效控制消毒副产物的生成.为实现紫外/电产过氧化氢工艺在果蔬清洗中的应用,开发了电产过氧化氢系统,以空气自扩散的方式对碳-聚四氟乙烯电极生产过氧化氢进行了寿命测试和成本评估.结果表明,该系统可在日常使用条件下使用长达1a以上,运行成本约为直接购买过氧化氢的3.9％～13.5％.
基于电力数据的实时性、精确性、覆盖面广等优势,构建水泥企业的电碳指数,运用机器学习算法研究水泥企业生产净购入电量与二氧化碳排放总量的关系,分别建立单样本日度电碳监测模型和多样本年度电碳监测模型,结果表明,9种回归方法中表现最佳的Lasso模型拟合优度(R2)为0.915和0.831,水泥企业电碳指数的关键影响因素主要为熟料生产电力排放因子和熟料工段耗电量在全厂用电量的占比,验证了电力相关数据在碳排放监测模型中的重要性,模型应用将有效提高水泥企业的碳排放监测效率和降低碳排放监测成本.
