中山市人为源大气污染物排放清单及特征研究

建立了中山市2017年人为源大气污染物排放清单。结果发现，SO₂、NOx、CO、PM₁₀、PM_2.5、BC、OC、VOCs和NH₃排放总量分别为4164、38231、92978、21492、6469、586、1199、56910和7059 t。SO₂的最大排放源是化石燃料固定燃烧源；NOx、CO和BC的最大排放源是道路移动源；PM₁₀和PM_2.5的最大排放源是扬尘源；VOCs的最大排放源是溶剂使用源；NH₃的最大排放源是农业源；其他源中的餐饮油烟源是OC的重要排放源。SO₂、PM₁₀、PM_2.5和VOCs的排放主要集中在中山市北部和东部工业区，以及中心城区，NOx的排放多分布在交通较为密集的交通干线和高速路区域，NH₃的排放主要集中在中山市南部和北部。     

烘焙生物质-煤混烧条件下灰的腐蚀行为

生物质经烘焙后物化特性显著改善,可大规模替代煤炭进行燃烧发电,降低CO₂排放。然而,燃烧过程中灰沉积、腐蚀等问题亟需解决,烘焙过程对生物质燃烧中腐蚀行为的影响尚缺乏系统的研究。鉴于此,选取玉米秆、麦草2种典型生物质,在固定床反应器上制备其烘焙样,通过逐级提取结合ICP-MS、IC测试,探究烘焙对生物质中关键成灰元素的赋存形态及含量的影响。在沉降炉系统进行烘焙前后生物质、2种动力用煤单烧以及各生物质样品与煤混烧试验,并收集其总灰。选取12CrMoVG钢为腐蚀试验金属材料,使用基于水平管式炉的腐蚀试验系统,探究了550℃时,HCl存在的模拟烟气气氛下,单烧灰负载的腐蚀情况,以及HCl、SO₂共同存在的模拟烟气气氛下混烧灰负载的腐蚀情况,称重获得各工况下腐蚀增重,并通过SEM-EDS分析了腐蚀后样品形貌及成分特征。最后,通过不同HCl浓度下的腐蚀试验,揭示了烘焙对生物质-煤混烧的腐蚀倾向影响。结果表明,玉米秆和麦草中Cl和K含量较高。经过270℃烘焙,玉米秆和麦草中Cl分别释放了17.84%和38.76%;S分别释放了7.78%、20.98%;Na...     

北京市某街道采暖期与非采暖期环境空气颗粒物(PM2.5)组分特征及来源分析初探

本文于采暖期(2021 年 12 月～2022 年 1 月)和非采暖期(2022 年 3 月～4 月)对北京市某街道共计两个点位进行环境空气颗粒物PM_2.5浓度及组分(水溶性离子、碳质组分、无机元素)监测。结果显示：两个点位在采暖期和非采暖期 PM_2.5浓度分别为 37 μg/m³、39 μg/m³,水溶性离子中以 NO₃^-、SO₄^2-、NH₄⁺为主要组分,碳质组分以 OC 为主,无机元素中 Fe、Zn、Al、S、Si 五种元素的浓度相对较高。通过质量重构结果表明,OM、NO₃^-、SO₄^2-、NH₄⁺、地壳物质的占比较高(超过 90 %),在采暖期期间 PM_2.5组分主要来源于化石燃料燃烧和机动车排放的 NO_...     

贵州某煤矿区周边耕地土壤有效态砷提取方法比较

为探究操作简单、高效且适合某煤矿区周边土壤砷有效态的提取方法,贵州以某矿区周边土壤(4个点位S1～S4)为研究对象,选择5种提取剂(DPTA-CaCl₂-TEA、KH₂PO₄、NH₄H₂PO₄、NaHCO₃、CaCl₂)对土壤中有效态砷进行提取,筛选出高效的提取剂。结果表明：(1)5种提取剂对土壤中有效态砷提取效果差异较大,提取能力大小依次为：NH₄H₂PO₄> KH₂PO₄> CaCl₂> NaHCO₃> DPTA-CaCl₂-TEA;(2)NH₄H₂PO₄溶液对土壤有效态砷的提取量分别为13.20(S1),10.95(S2),12.64(S3),5...     

不同温度下NH4H2PO4-(NH2)2CO-H2O体系溶解度的测定

采用等温溶解平衡法研究303.15,323.15,333.15,343.15 K下三元体系NH₄H₂PO₄-(NH₂)₂CO-H₂O的固液相平衡关系，平衡固相组成采用湿渣法与X射线衍射法相结合的方法进行鉴定。结果表明：三元体系NH₄H₂PO₄-(NH₂)₂CO-H₂O在各个温度下均有1个共饱和点、2条单变量曲线、3个结晶区。运用Wilson模型和NRTL模型对研究体系进行关联计算，结果表明：NH₄H₂PO₄-(NH₂)₂CO-H₂O体系的Wilson模型关联值的RAD=2.68%,RMSD=0.11;NRTL模型关联值的RAD=1.78%,RMSD=0.71,溶解度理论计算值与实验值吻合良好。最后...     

湿法除尘技术进展及变温多相流脱除PM2.5的新方法

分析对比了工业化国家应对工业增长控制PM_2.5排放的策略与技术措施,特别是荷兰在充分的技术经济性研究基础上制定50% PM减排目标、相当于9 mg·m^-3工业尾气颗粒物允许排放浓度标准,值得我国借鉴。工业源颗粒物排放占比前5的冶金、石油加工、化工、建材和食品加工业颗粒排放物呈现PM_1.0的粒度分布峰值特征,应首选湿法静电沉降类(Wet-ESP)减排技术,但其经济性未必适合我国大规模基础工业发展阶段。提出废气-废水多相交叉流阵列变温脱除PM_2.5的新方法,利用气流横掠液柱传热传质产生的速度场、温度场和浓度场推动微粒向气液界面运动,使所有单液柱均成为独立的PM_2.5分离单元,其串-并联组合结构使阵列具有很高的PM_2.5分离总效率。模型预测单元数n=200的交叉流阵列用于810kW大功率钻井柴油机(排气量4906 kg·h^-1干气)尾气碳烟PM_2.5减排的效率为91.4%,现场模型试验实测值略大于80%,理论与实践均表明该方法以废治废、经济可行。     

民用方型蜂窝煤燃烧采暖的减排效果及经济性分析

采用低排放-低成本的洁净型煤取暖技术路径有效解决散煤燃烧取暖带来的环境污染问题,是现阶段实现我国欠发达农村地区清洁取暖的有效举措之一。系统评估了2种新型民用方型蜂窝煤配套专用炉具燃烧采暖的减排效果和经济性。结果表明,无烟煤方型蜂窝煤和烟煤方型蜂窝煤基于单位燃料质量的PM_2.5排放因子分别为0.09和0.43 g/kg、CO排放因子为51.61和38.35 g/kg、NO_x排放因子为0.72和0.63 g/kg。与散煤相比,PM_2.5可减排96.16%和81.64%、CO可减排85.15%和88.97%、NO_x可减排53.25%和59.09%。无烟煤方型蜂窝煤、烟煤方型蜂窝煤和散煤的固硫率分别为61.55%、70.76%和20.93%。相比散煤,方型蜂窝煤的PM_2.5、CO和NO_x排放较低,且具有较好的固硫效果,可有效减少SO₂排放。方型蜂窝煤取暖的减排效果不仅受燃料性质影响,其配套专用炉具的进料方式、燃烧方式、供风系统设计等对其减排效...     

（NH2）2CO-NH4H2PO4-H2O三元系10 ℃相平衡研究

采用等温溶解平衡法研究了三元系（NH₂）₂CO-NH₄H₂PO₄-H₂O在10 ℃时的相平衡,并采用湿渣法与X射线衍射相结合的方法鉴定了平衡固相的组成与结构。结果表明,该体系为简单共饱和型,无复盐或固溶体生成,共饱点的质量组成（以质量分数计）：尿素,40.03%;磷酸一铵,13.92%;水,46.05%。相图中有2条单变量曲线,相图被划分为4个区域：不饱和区、（NH₂）₂CO结晶区、NH₄H₂PO₄结晶区和（NH₂）₂CO-NH₄H₂PO₄混合结晶区。用Wilson方程与NRTL方程对实验数据关联计算,实验值与计算值吻合度较高,2个热力学模型计算值与实验值的RAD分别为0.37%和0.71%,RMSD分别为0.20和0.29。     

太原市沙尘期间PM2.5变化特征

利用PM_2.5在线监测仪、在线气体/气溶胶监测仪(Marga)、半连续热光分析仪(OCEC)、在线重金属监测仪(CES)、单颗粒气溶胶质谱仪(SPAMS)分析了太原市沙尘期间PM_2.5浓度、组分变化特征及来源情况。研究表明,沙尘期间,环境空气质量迅速恶化,PM_2.5浓度升高明显。在PM_2.5组分分析中,沙尘期间,SO₄^2-、NO₃^-、NH₄⁺二次离子浓度有所下降,OC、EC变化不大,金属元素浓度增幅明显。PM_2.5在线来源解析表明,沙尘期间扬尘源占比大幅增加,矿物质颗粒物和含左旋葡聚糖颗粒物占比也有不同程度增加。     

化学团聚促进电除尘脱除PM2.5的实验研究

燃煤排放细颗粒物是大气环境PM_2.5增加的重要来源。采用燃煤热态实验系统,进行了在电除尘器入口烟气添加化学团聚剂以及协同脱硫废水蒸发处理促进电除尘脱除PM_2.5的实验研究。实验考察了团聚剂添加前后PM_2.5浓度及其粒度分布的变化,以及团聚剂浓度、添加点烟温、团聚剂溶液pH、烟气量、雾滴粒径等对PM_2.5脱除效果的影响。结果表明,添加化学团聚液后,通过润湿作用、液桥力和吸附架桥作用可增强PM_2.5之间的接触并促进团聚长大,PM_2.5增大到原先的4倍左右,典型工况下电除尘器出口PM_2.5浓度降低40%以上。增加团聚液浓度可促进PM_2.5的脱除;适当降低团聚液pH有利于PM_2.5的团聚。喷脱硫废水,电除尘器出口PM_2.5浓度变化不大,加团聚剂后出口细颗粒物浓度降低。     

交互四元体系K+,NH4+//Cl-,H2PO4——H2O 在313.15 K时相平衡研究

采用等温溶解平衡法研究了交互四元体系K⁺,NH₄⁺//Cl^-,H₂PO₄^--H₂O以及子体系KCl-NH₄Cl-H₂O在313.15 K时的固-液相平衡关系,并根据实验数据绘制了四元体系及子体系的相关相图和水图,采用湿渣法与X射线衍射相结合的方法对平衡固相进行鉴定。实验结果表明,三元体系KCl-NH₄Cl-H₂O是一个部分互溶体系,相图有一个共结晶点、2条单变量曲线、5个结晶区;交互四元体系K⁺,NH₄⁺//Cl^-,H₂PO₄^--H₂O中形成了（K,NH₄）Cl和（K,NH₄）H₂PO₄两种固溶体,该四元相图包括2个共饱和点、5条单变量曲线及4个结晶区。实验结果可为该体系的共结晶研究、相应的模型拟合计算提供必要基础数据。     

KH2PO4-KCl-H2O、NH4H2PO4-NH4Cl-H2O三元体系283.15 K相平衡研究

采用等温溶解平衡法研究了三元体系KH₂PO₄-KCl-H₂O、NH₄H₂PO₄-NH₄Cl-H₂O在283.15 K时的相平衡,并用湿渣法与X射线衍射相结合的方法鉴定了平衡固相的组成与结构。结果表明,三元体系KH₂PO₄-KCl-H₂O和NH₄H₂PO₄-NH₄Cl-H₂O为简单共饱和型,无固溶体或加合物形成,每个相图包含1个不变点、2条单变量曲线和3个结晶区。运用Pitzer电解质溶液理论计算了简单三元体系KH₂PO₄-KCl-H₂O、NH₄H₂PO₄-NH₄Cl-H₂O的饱和溶解度数据,结果表明,KH₂PO₄-KCl-H₂O体系的相对平均偏差为0.046,均方根偏差为0.29,NH₄H₂PO₄-NH₄Cl-H₂O体系的相对平均偏差为0.044,均方根偏差为0.31,溶解度理论计算结果与实验值基本一致。     

Dielectric properties and X-T phase diagram of mixed K1-x (NH4)xH2PO4 crystals

The x-T phase diagram of K_1-x (NH₄)_xH₂PO₄ mixed crystals have been plotted on the base of results of dielectric measurements and literature data.     

Monte carlo study of a model for the mixed crystal Rb1-x, (NH4)xH22PO4

A microscopic model for the mixed crystal Rb_1-x(NH₄)_xH₂PO₄ is introduced which takes into account the acid protons as well as the NH₄ groups. Using Monte Carlo simulation, the topology of the experimentally determined phase diagram is reproduced rather well, including the onset of freezing into a glasslike state.     

Solid state protonic conductor NH4PO3–(NH4)2Mn(PO3)4 for intermediate temperature fuel cells

A new proton-conductive composite of NH₄PO₃–(NH₄)₂Mn(PO₃)₄ was synthesized and characterized as a potential electrolyte for intermediate temperature fuel cells that operated around 250 °C. Thermal gravimetric analysis and X-ray diffraction investigation showed that (NH₄)₂Mn(PO₃)₄ was stable as a supporting matrix for NH₄PO₃. The composite conductivity, measured using impedance spectroscopy, improved with increasing the molar ratio of NH₄PO₃ in both dry and wet atmospheres. A conductivity of 7 mS cm⁻¹ was obtained at 250 °C in wet hydrogen. Electromotive forces measured by hydrogen concentration cells showed that the composite was nearly a pure protonic conductor with hydrogen partial pressure in the range of 10²–10⁵ Pa. The proton transference number was determined to be 0.95 at 250 °C for 2NH₄PO₃–(NH₄)₂Mn(PO₃)₄ electrolyte. Fuel cells using 2NH₄PO₃–(NH₄)₂Mn(PO₃)₄ as an electrolyte and the Pt–C catalyst as an electrode were fabricated. Maximum power density of 16.8 mW/cm² was achieved at 250 °C with dry hydrogen and dry oxygen as the fuel and oxidant, respectively. However, the NH₄PO₃–(NH₄)₂Mn(PO₃)₄ electrolyte is not compatible with the Pt–C catalyst, indicating that it is critical to develop new electrode materials for the intermediate temperature fuel cells.     

Inhibition of different types of inert dust on aluminum powder explosion

Aluminum powder explosion accidents occurred frequently, but the mechanism of aluminum powder explosion is unclear. Therefore, the inhibitive effect of aluminum powder explosion plays a key role. To evaluate the inhibition capacity of different kinds of carbonates and phosphates: NaH₂PO₄, (NH₄)₂HPO₄, NH₄H₂PO₄, KHCO₃ and NaHCO₃ on aluminum deflagrations, a standard 20-L spherical chamber was used to determine the explosion severity, characterized by the maximum explosion pressure (P_max). New parameters have been proposed: the minimum significant inert concentration (MSIC) and the minimum complete inert concentration (MCIC), which characterized the effect of inert. Experimental results showed that from the minimum significant inert concentration (MSIC) and the minimum complete inert concentration (MCIC), phosphate can have a significant inhibiting effect. 40% NaH₂PO₄ can totally inert the aluminum explosion, and 50% (NH₄)₂HPO₄ or 50% NH₄H₂PO₄ can also suppress the explosion. Through simulation, phosphate mainly acts via a chemical inhibition pathway, which inhibits the reaction of aluminum powder and oxygen by catalyzing the recombination of H atoms and O atoms. Carbonate performs inhibition in chemically, producing CO₂, diluting the oxygen around the aluminum powder. Studies indicated that the explosion pressure of the mixture decreases as the concentration of inert dust increases. However, when the concentration of carbonates was low, SEEP (suppressant enhanced explosion parameter) phenomenon was found. This research work has a potential industrial application in high hazard aluminum working condition, which can help decrease the explosion pressure and reduce the accident loss.     

球形LiMnPO4/C正极材料的喷雾干燥法制备及性能研究

以氢氧化锂、乙酸锰、磷酸二氢铵和聚乙二醇为原料,采用一次喷雾干燥法制备了球形LiMnPO₄/C正极材料,并研究了煅烧温度对球形LiMnPO₄/C样品形貌、结构和电化学性能的影响。通过X射线衍射（XRD）和场发射扫描电镜（SEM）对其进行了结构和形貌的表征。结果表明,经700 ℃焙烧的LiMnPO₄/C为橄榄石型结构,在SEM下呈规则的球形,由粒径约为50 nm的一维纳米颗粒堆积而成。该样品在室温0.1C倍率下首次放电比容量可达148 mA·h/g,循环80圈后的放电比容量依然在140 mA·h/g左右,容量保持率为94.6%。     

313.15 K下三元体系KH2PO4-(NH2)2CO-H2O相平衡研究

采用等温溶解平衡法研究了三元体系KH₂PO₄-(NH₂)₂CO-H₂O在313.15 K下的溶解度数据,根据溶解度数据绘制了等温相图,采用湿渣法和X射线衍射法对平衡固相的组成进行了分析。结果表明三元体系KH₂PO₄-(NH₂)₂CO-H₂O为简单共饱和型体系,相图中有1个共饱和点、2条单变量曲线、3个结晶区;采用Wilson和NRTL模型关联该体系的溶解度数据,关联计算值与实验值基本吻合。其中Wilson模型的相对平均偏差(RAD)和均方根差(RMSD)分别为3.34%、0.17%;NRTL模型的RAD和RMSD分别为10.53%、0.38%。对比三元体系KH₂PO₄-(NH₂)₂CO-H₂O在多个温度下相平衡的结晶区域,发现在中、低温阶段降低温度有利于尿素[(...     

Long-term cyclability of nanostructured LiFePO4

Amorphous LiFePO₄ was obtained by lithiation of FePO₄ synthesized by spontaneous precipitation from equimolar aqueous solutions of Fe(NH₄)₂(SO₄)₂·6H₂O and NH₄H₂PO₄, using hydrogen peroxide as oxidizing agent. Nano-crystalline LiFePO₄ was obtained by heating amorphous nano-sized LiFePO₄ for different periods of time. The materials were characterized by TG, DTA, X-ray powder diffraction, scanning electron microscopy (SEM) and BET. All materials showed very good electrochemical performance in terms of energy and power density. Upon cycling, a capacity fading affected the materials, thus reducing the electrochemical performance. Nevertheless, the fading decreased upon cycling and after the 200th cycle the cell was able to cycle for more than 500 cycles without further fading.