橡胶坝对河流沉积物氮转化功能基因丰度和营养盐的影响

沉积物氮转化功能微生物是河流脱氮和水体净化的重要生物因素.为探讨橡胶坝对沉积物氮转化功能基因丰度及氮营养盐的影响，本研究以沂河沂水城区蓄水段为研究对象，从橡胶坝前不同距离采集沉积物，利用实时荧光定量PCR（qPCR）方法研究了沉积物的反硝化功能基因（nirS、nirK、nosZ）、厌氧氨氧化功能基因（AMX）和反硝化型甲烷厌氧氧化功能基因（pmoA）的丰度及沉积物营养盐特征.结果表明：橡胶坝促进了沉积物中nirK、nirS、nosZ和pmoA基因的聚集，反硝化功能基因nirK、nirS、nosZ丰度在坝前120 ~330 m范围内较高；橡胶坝促进了沉积物NH4+、NO3-、TN、TP、TOC、有机质（OM）等营养盐的滞留，主要在120 ~360 m区域聚集，多元线性回归模型拟合度较高.相关分析表明，16S rRNA、nirK、nirS、nosZ、pmoA基因丰度与环境因子NH4+、NO3-、TN、OM、TOC、孔隙度呈正相关；PCA分析结果表明，随着沉积物环境因子主成分的增长，氮转化功能基因丰度主成分呈升高趋势.橡胶坝可促进沂河沉积物氮素等营养盐的滞留和氮转化功能微生物的聚集.     

磁改性羊粪衍生ZVI-生物炭的制备及其活化过一硫酸盐降解AO7特性研究

以羊粪为原料，制备磁改性羊粪衍生ZVI-生物炭复合材料 （SMF₈₀₀），通过BET、SEM、XRD、N₂吸附-脱附等温线等对其表面形貌及晶体结构进行表征，并采用序批实验考查活化剂和过一硫酸盐 （PMS） 投加量、温度、溶液初始pH、无机阴离子等因素对AO7降解效率影响.结果表明，SMF₈₀₀拥有高度石墨化及多孔结构，在最佳条件下 （PMS=0.8 g·L^-1、SMF₈₀₀=0.5 g·L^-1、AO7=20 mg·L^-1、T=25 ℃），40 min内AO7能被完全降解，在弱酸条件下有利于脱色，且活化剂经过3次循环使用后仍具有良好的活化效率.猝灭实验和XPS测试结果表明，自由基 （SO4- ?、·OH、O₂^·- ） 和非自由基途径 （¹O₂） 协同作用于AO7的降解，其中以Fe⁰还原PMS产生SO4- ?的自由基途径占主导地位，以Fe⁰诱导碳电子、生物炭表面含氧官能团 （C-OH 和COOH） 激活PMS产生¹O₂为辅，而SMF₈₀₀石墨化及大量的sp²-C结构为电子转移提供良好的场所.综上，本研究设计制备了一种新型的生物炭基ZVI活化剂，以期为有机废水高效、低成本的处理方法提供新的技术支撑，同时也为粪源资源化利用提供新的途径.     

基于QAR数据的中国民航飞行排放清单估计研究

近年来中国民用航空迅速发展，产生了大量的排放物，需要准确的排放清单来评估民航行业对环境的影响.针对现有的研究在估算精度与覆盖范围上存在的不足，本文利用了飞机QAR数据构建了估算单次飞行燃油消耗量与包括HC、CO、NOx、PM、SO2以及CO2在内的排放物生成量的方法，并采用自下而上的方法，对2018年1月—2021年11月在中国国内民航活动产生的排放物进行了统计.在估算时考虑了机型、起飞机场和降落机场对飞行各阶段持续时间的影响.从排放模式来看，不同机场的飞行在LTO阶段的平均排放量存在差异，总的来说，机场规模越大，单次飞行排放量越多，大多数排放物在CCD阶段排放且该阶段的排放量与飞行时间存在明显的线性关系.2018年和2019年的排放量保持了上升，CO2排放量分别为73.17 ×10⁶ t和76.85 ×10⁶ t，但自从2019年12月受到新冠疫情影响后，排放量与航班量随疫情控制情况波动，2020年和2021年1月—11月CO2排放量分别为61.51 ×10⁶ t和60.08 ×10⁶ t.为了探究新冠疫情对排放物的影响，采用差分整合移动平均自回归模型对无疫情时2019年12月之后的排放量进行了估计，结果表明新冠疫情爆发后，到2021年11月为止各种排放物的排放量减少了20%左右.     

一体式部分亚硝化-厌氧氨氧化工艺污泥膨胀发生和恢复过程中胞外聚合物变化特征

胞外聚合物（Extracellular Polymeric Substances， EPS）对污泥沉降具有重要作用.以一体式部分亚硝化-厌氧氨氧化工艺为对象，针对出现的污泥膨胀问题，通过停止投加乙酸钠、调整SRT和曝停比等措施控制了污泥膨胀，并考察整个过程中胞外聚合物变化特征.结果表明，阶段I~II（0~77 d），SVI升至215.86 mL?g^-1，TN去除率仍稳定在60.88%；阶段III（78~109 d），SVI维持在210.16 mL?g^-1，TN去除率下降至32.19%； 阶段IV（110~140 d），SVI下降至107.53 mL?g^-1，TN去除率也恢复至54.55%，AOB、NOB和ANAMMOX活性分别恢复至0.42、0.06、0.20 g?g^-1?d^-1.污泥膨胀得到控制以后，溶解性EPS （Solubility EPS， S-EPS）、溶解性蛋白（Solubility PN， S-PN）从243.15、213.25 mg?g^-1分别下降至110.97、49.52 mg?g^-1.三维荧光光谱分析表明，投加乙酸钠PN含量呈上升趋势，PS含量下降.PICRUSt2对蛋白质（PN）、多糖（PS）代谢分析也表明，停止投加乙酸钠以后，氨基酸代谢基因丰度降低，疏水性增强，PS更多地转为内源性有机物供微生物利用.     

塔克拉玛干沙漠和青藏高原地区沙尘气溶胶光学特性及其加热率的时空分布特征

沙尘不同的垂直分布对大气的加热作用不同，通过卫星观测结合数值模拟，可以更清楚地了解沙尘辐射加热作用，有利于理解沙尘对该地区大气热结构的影响机制.因此，本研究利用CALIPSO气溶胶产品和SBDART模式，分析了2007—2020年塔克拉玛干沙漠和青藏高原沙尘气溶胶及其短波加热率的时空分布特征.结果表明，塔克拉玛干沙漠和青藏高原的年平均沙尘气溶胶光学厚度（DAOD，532 nm）分别为0.300~0.350和0.086~0.108，平均值分别为0.328和0.097.塔克拉玛干沙漠季节平均DAOD的最大、最小值分别出现在春季和冬季，而青藏高原的 最大、最小值分别出现在夏季和秋季.塔克拉玛干沙漠和青藏高原的沙尘消光系数（σD）最大值分别出现在春季和夏季.2007—2020年，两地的σD在春季均呈增加趋势，而在秋季则呈减小趋势.春季和夏季的短波沙尘加热率（SW DHR）均大于其它两个季节，其中春季最大，塔克拉玛干沙漠上空冬季最弱，青藏高原上空秋季最弱.春夏季，青藏高原北坡存在较强沙尘加热层，其顶部高于5 km，其强度及高值区从春季到冬季 逐渐减小.从年变化来看，春季短波加热率呈加强趋势，秋季呈减弱趋势.柴达木盆地是青藏高原上空沙尘加热率（DHR）最高的区域，对高原沙尘输送和辐射加热有重要作用.     

高锰酸钾凝胶缓释剂的制备及其缓释去除水中三氯乙烯

本研究开发一种结合原位化学氧化和二氧化硅溶胶-凝胶的可控氧化剂释放技术，制备出一种高锰酸钾（KMnO₄）凝胶缓释剂（SRPG）.优化SPRG的制备条件和探究影响其在水中缓释效率的因素，并考察其对不同氯代烃的降解效果.结果表明：二氧化硅溶胶的质量分数、KMnO₄的含量及pH对SRPG凝胶化过程有显著的影响；提高缓释剂中KMnO₄的含量和降低二氧化硅溶胶质量分数，可有效提高SRPG中KMnO₄的释放速率，当KMnO₄质量分数为6.51‰，二氧化硅溶胶质量分数为40%，KMnO₄的释放符合拟一阶动力学，释放速率kobs=0.83 h^-1（R²=0.9750），且12 h后KMnO₄释放率为82.7%；SRPG可有效降解水中氯代烃污染物，其中对三氯乙烯（TCE）的去除效果最佳，反应24 h可去除水中98%的TCE.因此，SRPG在原位化学氧化修复土壤和地下水中氯代烃的实际工程中具有良好的应用前景.     

外源Cd（Ⅱ）胁迫Alcaligenes faecalis过程中阴离子对 EPS产量及其特性的影响

微生物产生EPS受多种因素影响，其中重金属阳离子的作用较为明显，但其对应的阴离子的作用仍不明确.研究了SO₄^2-、NO₃^-和Cl^-对应的3种Cd（Ⅱ）化合物胁迫/诱导下Alcaligenes faecalis EPS的产量、组分变化及其吸附性能.结果表明，20 mg·L^-1 Cd（NO₃）₂的胁迫效果最为明显，EPS产量达到109.17 mg·g^-1，其中蛋白质含量达到89.46 mg·g^-1，较Control-EPS提高50%以上.在此条件下，Cd（NO₃）₂-EPS对Cd（Ⅱ）吸附量最高，达到300.20 mg·g^-1，较胁迫前增加41.83%.三维荧光（3D-EEM）、红外光谱（FTIR）和X射线光电子能谱（XPS）分析表明，胁迫后的EPS，尤其是Cd（NO₃）₂-EPS中C?O、C-O/C-N含量增幅明显，在吸附Cd（Ⅱ）中发挥了重要作用.实验结果表明，在Cd（NO₃）₂胁迫/诱导下，Alcaligenes faecalis可产生特异EPS，具有优异的吸附性能.本文为制备生物制剂以处理含重金属废水提供了重要理论指导.     

Competitive role of nitrogen functionalities of N doped GO and sensitizing effect of Bi2O3 QDs on TiO2 for water remediation

The promising solar irradiated photocatalyst by pairing of bismuth oxide quantum dots (BQDs) doped TiO₂ with nitrogen doped graphene oxide (NGO) nanocomposite (NGO/BQDs-TiO₂) was fabricated. It was used for degradation of organic pollutants like 2,4-dichlorophenol (2,4-DCP) and stable dyes, i.e. Rhodamine B and Congo Red. X-ray diffraction (XRD) profile of NGO showed reduction in oxygenic functional groups and restoring of graphitic crystal structure. The characteristic diffraction peaks of TiO₂ and its composites showed crystalline anatase TiO₂. Morphological images represent spherical shaped TiO₂ evenly covered with BQDs spread on NGO sheet. The surface linkages of $\text{NO}?\mathrm{O}?\text{Ti}$, $\mathrm{C}?\mathrm{O}?\text{Ti}$, $\mathrm{B}\mathrm{i}?\mathrm{O}?\text{Ti}$ and vibrational modes are observed by Fourier transform infrared spectroscopy (FTIR) and Raman studies. BQDs and NGO modified TiO₂ results into red shifting in visible region as studied in diffused reflectance spectroscopy (DRS). NGO and BQDs in TiO₂ are linked with defect centers which reduced the recombination of free charge carriers by quenching of photoluminescence (PL) intensities. X-ray photoelectron spectroscopy (XPS) shows that no peak related to $\mathrm{C}?\mathrm{O}$ in NGO/BQDs-TiO₂ is observed. This indicated that doping of nitrogen into GO has reduced some oxygen functional groups. Nitrogen functionalities in NGO and photosensitizing effect of BQDs in ternary composite have improved photocatalytic activity against organic pollutants. Intermediate byproducts during photo degradation process of 2,4-DCP were studied through high performance liquid chromatography (HPLC). Study of radical scavengers indicated that ${\mathrm{O}}_2^{·?}$ has significant role for degradation of 2,4-DCP. Our investigations propose that fabricated nanohybrid architecture has potential for degradation of environmental pollutions.     

Chemical and olfactive impacts of organic matters on odor emission patterns from the simulated construction and demolition waste landfills

The explosive increase of construction and demolition waste (CDW) caused the insufficient source separation and emergency disposal at domestic waste landfills in many developing countries. Some organic fractions were introduced to the CDW landfill process and resulted in serious odor pollution. To comprehensively explore the impacts of organic matters on odor emission patterns, five CDW landfills (OIL), with organic matters/ inert CDW components (O/I) from 5% to 30%, and the control group only with inert components (IL) or organics (OL) were simulated at the laboratory. The chemical and olfactive characters of odors were evaluated using the emission rate of 94 odorants content (ER_total), theory odor concentration (TOC_total), and e-nose concentration (ER_ENC), and their correlations with waste properties were also analyzed. It was found that the main contributors to ER_total (IL: 93.0% NH₃; OIL: 41.6% sulfides, 31.0% NH₃, 25.9% oxygenated compounds) and TOC total (IL: 64.1% CH₃SH, 28.2% NH₃; OIL: 71.7% CH₃SH, 24.8% H₂S) changed significantly. With the rise of O/I, ER_total, TOC_total, and ER_ENC increased by 10.9, 20.6, and 2.1 times, respectively. And the organics content in CDW should be less than 10% (i.e., DOC<101.3 mg/L). The good regressions between waste properties (DOC, DN, pH) and ${\mathrm{ER}}_{\stackrel{?}{\mathrm{ENC}}}$ (r=0.86, 0.86, -0.88, p<0.05), ${\mathrm{TOC}}_{\stackrel{?}{\mathrm{total}}}$ (r=0.82, 0.79, -0.82, p<0.05) implied that the carbon sources and acidic substances relating to organics degradation might result in that increase. Besides, the correlation analysis results (${\mathrm{ER}}_{\stackrel{?}{\mathrm{ENC}}}$ vs. ${\mathrm{TOC}}_{\stackrel{?}{\mathrm{total}}}$, r=0.96, p<0.01; vs. ${\mathrm{ER}}_{\stackrel{?}{\mathrm{total}}}$, r=0.86, p<0.05) indicated that e-nose perhaps was a reliable odor continuous monitoring tool for CDW landfills.     

松香基三烯丙酯交联聚合树脂的合成及其对水中Pb（II）、Cd（II）和Cu（II）的吸附性能与机制

以自制的松香基三烯丙酯（triallyl maleopimarate， TAMP）为交联剂，通过悬浮聚合法合成了一种松香基三烯丙酯交联聚合树脂（triallyl maleopimarate-acrylic copolymer， TAMPA），采用红外光谱（FTIR）、扫描电镜（SEM）、N₂吸附脱附曲线和热重（TG）分析等方法对其物理化学结构及热稳定性等进行表征，采用批量吸附实验探讨了TAMPA投加量、溶液pH、温度、接触时间和离子强度等因素对TAMP树脂对Pb（II）、Cd（II）和Cu（II）重金属离子吸附性能的影响.结果表明，当pH值为2.0~5.0，TAMPA树脂对Pb（II）、Cu（II）和Cd（II）吸附量呈先增大后平缓的趋势，pH=5.0为最大值.随着离子溶液的增加对TAMP树脂去除重金属离子有抑制作用；吸附动力学符合准二级模型；Freundlich等温吸附模型可以较好地描述TAMPA对3种重金属的吸附；吸附热力学结果表明其能自发对相关金属离子进行吸附.以EDTA为洗脱剂，重复再生3次后TAMPA仍有可观的吸附性能.结合XPS和量子化学计算模拟结果，提出了TAMPA对Pb（II）、Cd（II）和Cu（II）的吸附作用机制，主要为重金属离子与材料基体中的C?O氧配位螯合作用.     

Modeling of spatial and temporal variations of ozone-NOx-VOC sensitivity based on photochemical indicators in China

Comprehensive air quality model with extensions (CAMx)-decoupled direct method (DDM) was used to simulate ozone-NO_x-VOCs sensitivity of for May–November in 2016–2018 in China. Based on the relationship between the simulated ozone (O₃) sensitivity values and the ratio of formaldehyde (HCHO) to NO₂ (FNR) and the ratio of production rate of hydrogen peroxide (H₂O₂) to production rate of nitric acid (HNO₃) ($P_{{\mathrm{H}}_2{\mathrm{O}}_2}/P_{\text{HN}{\mathrm{O}}_3}$), the localized range of FNR and $P_{{\mathrm{H}}_2{\mathrm{O}}_2}/P_{\text{HN}{\mathrm{O}}_3}$ thresholds in different regions in China were obtained. The overall simulated FNR values are about 1.640–2.520, and $P_{{\mathrm{H}}_2{\mathrm{O}}_2}/P_{\text{HN}{\mathrm{O}}_3}$ values are about 0.540–0.830 for the transition regime. Model simulated O₃ sensitivities or region specific FNR or $P_{{\mathrm{H}}_2{\mathrm{O}}_2}/P_{\text{HN}{\mathrm{O}}_3}$ thresholds should be applied to ensure the accurate local O₃ sensitivity regimes. Using the tropospheric column FNR values from ozone monitoring instrument (OMI) satellite data as an indicator with the simulated threshold values, the spatial distributions of O₃ formation regimes in China are determined. The O₃ sensitivity regimes from eastern to central China are gradually from VOC-limited, transition to NO_x-limited spatially, and moving toward to transition or NO_x-limited regime from 2005 to 2019 temporally.     

Origins of black carbon from anthropogenic emissions and open biomass burning transported to Xishuangbanna, Southwest China

Black carbon (BC) has importance regarding aerosol composition, radiative balance, and human exposure. This study adopted a backward-trajectory approach to quantify the origins of BC from anthropogenic emissions ($\mathrm{B}{\mathrm{C}}_{\text{An}}$) and open biomass burning ($\mathrm{B}{\mathrm{C}}_{\text{BB}}$) transported to Xishuangbanna in 2017. Haze months, between haze and clean months, and clean months in Xishuangbanna were defined according to daily PM_2.5 concentrations of >75, 35–75, and <35 µg/m³, respectively. Results showed that the transport efficiency density (TED) of BC transported to Xishuangbanna was controlled by the prevailing winds in different seasons. The yearly contributions to the effective emission intensity of $\mathrm{B}{\mathrm{C}}_{\text{An}}$ and $\mathrm{B}{\mathrm{C}}_{\text{BB}}$ transported to Xishuangbanna were 52% and 48%, respectively. However, when haze occurred in Xishuangbanna, the average $\mathrm{B}{\mathrm{C}}_{\text{An}}$ and $\mathrm{B}{\mathrm{C}}_{\text{BB}}$ contributions were 23% and 77%, respectively. This suggests that open biomass burning (BB) becomes the dominant source in haze months. Myanmar, India, and Laos were the dominant source regions of BC transported to Xishuangbanna during haze months, accounting for 59%, 18%, and 13% of the total, respectively. Furthermore, India was identified as the most important source regions of $\mathrm{B}{\mathrm{C}}_{\text{An}}$ transported to Xishuangbanna in haze months, accounting for 14%. The two countries making the greatest contributions to $\mathrm{B}{\mathrm{C}}_{\text{BB}}$ transported to Xishuangbanna were Myanmar and Laos in haze months, accounting for 55% and 13%, respectively. BC emissions from Xishuangbanna had minimal effects on the results of the present study. It is suggested that open BB in Myanmar and Laos, and anthropogenic emissions in India were responsible for poor air quality in Xishuangbanna.     

Enhanced phosphate removal using zirconium hydroxide encapsulated in quaternized cellulose

Zirconium-based materials are efficient adsorbent for aqueous phosphate removal. However, current zirconium-based materials still show unsatisfied performance on adsorption capacity and selectivity. Here, we demonstrate a zirconium hydroxide encapsulated in quaternized cellulose (QC–Zr) for the selective phosphate removal. Zirconium hydroxide nanoparticles were simultaneously generated in situ with the QC framework and firmly anchored in the three-dimensional (3D) cross-linked cellulose chains. The maximum P adsorption capacity of QC–Zr was 83.6 mg P/g. Furthermore, the QC–Zr shows high P adsorption performance in a wide pH range, generally due to the electrostatic effects of quaternized cellulose. The enhanced adsorption of P was also achieved in the presence of competing anions (including Cl^?, NO₃^?, ${\text{SO}}_4^{2?}$, ${\text{SO}}_4^{\mathrm{4}?}$) and humic acid (HA) even at a molar ratio up to 20 levels. The column adsorption capacity of QC–Zr reached 4000 bed volumes (BV) at EBCT = 0.5 min as the P concentration decreased from 2.5 to 0.5 mg/L. Mechanism study revealed that both –N⁺(CH₃)₃ groups and zirconium hydroxide were involved in phosphate adsorption via electrostatic interactions between –N⁺(CH₃)₃ and phosphate, and the formation of zirconium hydrogen phosphate (Zr(HPO₄)x). The ³¹P nuclear magnetic resonance (NMR) study implied that P surface–precipitated and inner–sphere complexed with zirconium hydroxide at a ratio of 3:1.     

Experimental and theoretical studies on NO selective catalytic oxidation over α-MnO2

Based on the experimental and theoretical methods, the NO selective catalytic oxidation process was proposed. The experimental results indicated that lattice oxygen was the active site for NO oxide over the $\mathrm{\alpha }$-MnO₂(110) surface. In the theoretical study, DFT (density functional theory) and periodic slab modeling were performed on an $\mathrm{\alpha }$-MnO₂(110) surface, and two possible NO oxidation mechanisms over the surface were proposed. The non-defect $\mathrm{\alpha }$-MnO₂(110) surface showed the highest stability, and the surface O_s (the second layer oxygen atoms) position was the most active and stable site. O₂ molecule enhanced the joint adsorption process of two NO molecules. The reaction process, including O₂ dissociation and O=N-O-O-N=O formation, was calculated to carry out the NO catalytic oxidation mechanism over $\mathrm{\alpha }$-MnO₂(110). The results showed that NO oxidation over the $\mathrm{\alpha }$-MnO₂(110) surface exhibited the greatest possibility following the route of O=N-O-O-N=O formation. Meanwhile, the formation of O=N-O-O-N=O was the rate-determining step.     

Effects of sludge age on anaerobic acidification of waste activated sludge: Volatile fatty acids production and phosphorus release

Effects of sludge age on volatile fatty acids (VFAs) production and Phosphorus (P) release during anaerobic acidification of waste activated sludge (WAS) were investigated. Sequencing batch reactors (SBR) fed with simulating domestic sewage were applied to produce WAS of different sludge ages, and batch tests were used for anaerobic acidification. The maximum dissolved total organic carbon, release of  ${\text{PO}}_4^{3+}?\mathrm{P}$, and accumulation of acetate (C2), propionate (C3), butyrate (C4), and valerate (C5) decreased by 56.2%, 55.8%, 52.6%, 43.7%, 82.4% and 84.8%, respectively, as the sludge age of WAS increased from 5 to 40 days. Limited degradation of protein played a dominating role in decreasing DTOC and VFAs production. Moreover, the increase in molecular weight of organics and organic nitrogen content in the supernatant after acidification suggested that the refractory protein in WAS increased as sludge age extended. Although the production of C2, C3, C4, and C5 from WAS decreased as the sludge age increased, the proportions of C2 and C3 in VFAs increased, which might be due to the declined production of C5 from protein and the faded genus Dechlorobacter. Keeping sludge age of WAS at a relatively low level (<10 days) is more appropriate for anaerobic acidification of WAS as internal carbon sources and P resource.     

Measurement of tropospheric HO2 radical using fluorescence assay by gas expansion with low interferences

An instrument to detect atmospheric HO₂ radicals using fluorescence assay by gas expansion (FAGE) technique has been developed. HO₂ is measured by reaction with NO to form OH and subsequent detection of OH by laser-induced fluorescence at low pressure. The system performance has been improved by optimizing the expansion distance and pressure, the influence factors of HO₂ conversion efficiency are also studied. The interferences of RO₂ radicals were investigated by determining the conversion efficiency of RO₂ to OH during the measurement of HO₂. The dependence of the conversion of HO₂ on NO concentration was investigated, and low HO₂ conversion efficiency was selected to realize the ambient HO₂ measurement, where the conversion efficiency of RO₂ derived by propane, ethene, isoprene and methanol to OH has been reduced to less than 6% in the atmosphere. Furthermore, no significant interferences from PM_2.5 and NO were found in the ambient HO₂ measurement. The detection limits for HO₂ (S/N = 2) are estimated to 4.8 × 10⁵ cm^?3 and 1.1 × 10⁶ cm^?3 (${\rho }_{\mathrm{H}{\mathrm{O}}_2}$= 20%) under night and noon conditions, with 60 sec signal integration time. The instrument was successfully deployed during STORM-2018 field campaign at Shenzhen graduate school of Peking University. The concentration of atmospheric HOx radical and the good correlation of OH with j(O¹D) was obtained here. The diurnal variation of HOx concentration shows that the OH maximum concentration of those days is about 5.3 × 10⁶ cm^?3 appearing around 12:00, while the HO₂ maximum concentration is about 4.2 × 10⁸ cm^?3 appearing around 13:30.     

Adsorptive removal of phosphate by the bimetallic hydroxide nanocomposites embedded in pomegranate peel

This study aimed to fabricate new and effective material for the efficiency of phosphate adsorption. Two types of adsorbent materials, the zirconium hydroxides embedded in pomegranate peel (Zr/Peel) and zirconium-lanthanum hydroxides embedded in pomegranate peel (Zr–La/Peel) were developed. Scanning electronic microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) were evaluated to give insight into the physicochemical properties of these adsorbents. Zr–La/Peel exceeded the adsorption efficiency of Zr/Peel adsorbents in batch adsorption experiments at the same pH level. The peel as a host can strive to have a strong “shielding effect” to increase the steadiness of the entrenched Zr and La elements. La and Zr are hydroxide metals that emit many hydrogen ions during the hydrolysis reaction, which contribute to protonation and electrostatic attraction. The highest adsorption capacity of La–Zr/Peel for phosphate was calculated to be 40.21 mg/g, and pseudo second-order equation is very well fitted for kinetic adsorption. Phosphate adsorption efficiency was reduced by an increase of pH. With the background of coexisting Cl^?, little effect on adsorption efficiency was observed, while adsorption capacities were reduced by almost 20–30% with the coexistence of ${{\text{SO}}_4}^{2?}$, ${{\text{NO}}_3}^{?}$ and humic acid (HA).     

Effectiveness evaluation of water-sprinkling in controlling urban fugitive road dust based on TRAKER method: A case study in Baoding, China

Fugitive road dust (FRD) contributes a great deal to urban rainwater and air pollution and is commonly controlled by water-sprinkling in most Chinese cities. However, there is a lack of information on its effectiveness. We used the Testing Re-entrained Aerosol Kinetic Emissions from Roads (TRAKER) method to monitor different types of roads in Baoding city before and within 1 hr after water-sprinkling and obtained the road dirtiness index (a) and PM concentration in the road environment ($T_{\mathrm{T}}^{*}$), to evaluate the removal efficiency for PM deposited on the road surface (${\eta }_a$) and the reduction efficiency for the PM concentration in the road environment (${\eta }_{\text{PM}}$). The results give that the ${\eta }_a$ for three types of roads is ranked: branch road (87%-–100%) > major arterial road (80%-83%) > minor arterial road (68%-77%), and the ${\eta }_{\text{PM}}$ ranked: minor arterial road (70%) > branch road (46%-58%) > major arterial road (37%-53%). The ${\eta }_a$ and ${\eta }_{\text{PM}}$ varied non-linearly with time and presented a quadratic curve. The average effective control time (${\eta }_{\mathit{a}}$> 0) was 62 min on the major and minor arterial roads, and much longer than 1 hr on branch roads. The ${\eta }_{\text{PM}}$ values diminished completely by 72 min on average from the end of sprinkling for the three types of roads. Water-sprinkling can remove PM₁₀ particles from the road surface and reduce their concentration in the road environment more thoroughly than PM_2.5. Our findings could be helpful for controlling urban FRD emissions more efficiently and precisely.     

Retrieval of refractive index of ultrafine single particle using hygroscopic growth factor obtained by high sensitive surface plasmon resonance microscopy

When exposed to different relative humidities (RHs), the optical properties of atmospheric aerosols will change because of changes in the aerosol particle size and complex refractive index (RI), which will affect haze formation and global climate change. The potential contributions of ultrafine particles to the atmospheric optical characteristics and to haze spreading cannot be ignored because of their high particle number concentrations and strong diffusibility; measurement of the optical properties of wet ultrafine particles is thus highly important for environmental assessment. Therefore, a surface plasmon resonance microscopy with azimuthal rotation illumination (SPRM-ARI) system is designed to determine the RIs of single particle aerosols with diameters of less than 100 nm in the hygroscopic growth process. Measurements are taken using mixed single particles with different mass ratios. The RIs of mixed single aerosols at different RHs are retrieved by measuring the scattering light intensity using the SPRM-ARI system and almost all the RIs of the bicomponent particles with different mass ratios decrease with increasing water content under high RH conditions. Finally, for each of the bicomponent particles, the maximum standard deviations for the retrieved RI values are only $2.06\times {10}^{-3}$, $3.08\times {10}^{-3}$ and $3.83\times {10}^{-3}$, corresponding to the NaCl and NaNO₃ bicomponent particles with a 3:1 mass ratio at 76.0% RH, the NaCl and glucose particles with a 1:3 mass ratio at 89.0% RH, and the NaCl and OA particles with a 1:1 mass ratio at 78.0% RH, respectively; these results indicate that the high-sensitivity SPRM-ARI system can measure the RI effectively and accurately.     

Influence of modified biochar supported sulfidation of nano-zero-valent-iron (S-nZVI/BC) on nitrate removal and greenhouse gas emission in constructed wetland

In this study, the biochar (BC) produced from sawdust, sludge, reed and walnut were used to support sulfidation of nano-zero-valent-iron (S-nZVI) to enhance nitrate (${\text{NO}}_3^{-}$-N) removal and investigate the impact on greenhouse gas emissions. Batch experiment results showed the S-nZVI/BC_{sawdust (2:1, 500)}, S-nZVI/BC_{sludge (2:1, 900)}, S-nZVI/BC_{reed (2:1, 700)}, and S-nZVI/BC _{walnut (2:1, 700)} respectively improved ${\text{NO}}_3^{-}$-N removal efficiencies by 22%, 20%, 3% and 0.1%, and the selectivity toward N₂ by 22%, 25%, 22% and 18%. S-nZVI uniformly loaded on BC provided electrons for the conversion of ${\text{NO}}_3^{-}$-N to N₂ through Fe⁰. At the same time, FeS_x layer was formed on the outer layer of ZVI in the sulfidation process to prevent iron oxidation, so as to improve the electrons utilization efficiency After adding four kinds of S-nZVI/BC into constructed wetlands (CWs), the ${\text{NO}}_3^{-}$-N removal efficiencies could reach 100% and the N₂O emission fluxes were reduced by 24.17%-36.63%. And the average removal efficiencies of TN, COD, TP were increased by 21.9%, -16.5%, 44.3%, repectively. The increasing relative abundances of denitrifying bacteria, such as Comamonas and Simplicispira, suggested that S-nZVI/BC could also improve the process of microbial denitrification. In addition, different S-nZVI/BC had different effects on denitrification functional genes (narG, nirk, nirS and nosZ genes), methanotrophs (pmoA) and methanogenesis (mcrA). This research provided an effective method to improve ${\text{NO}}_3^{-}$-N removal and reduce N₂O emission in CWs.