生物质燃烧排放颗粒物中水溶性有机物的光学特性

采用紫外-可见光吸收光谱法（UV-vis）和激发-发射矩阵荧光光谱法（EEM）分析了典型生物质燃烧排放颗粒物(PM_2.5)中水溶性有机物（WSOM）的光学特性.结果表明,WSOM的SUVA₂₅₄、E₂₅₀/E₃₆₅和MAE₃₆₅值分别为1.79-2.60 m²·g^-1、4.56-7.65和0.66-1.17 m²·g^-1,说明生物质燃烧排放PM_2.5中WSOM具有较低的芳香度和分子量以及较弱的吸光能力.荧光光谱结果显示,WSOM产生荧光峰的主要范围为λ_Ex/λ_Em≈（230-250）/（335-380） nm和λ_Ex/λ_Em≈（260—290）/（330—360） nm,说明生物质燃烧排放PM_2.5中WSOM主要以类蛋白荧光物质为主;腐殖化指数（HIX）、荧光指...     

一株具有氢自养能力的固氮粘质沙雷氏菌的分离鉴定、代谢特征与功能基因检测

氢氧化细菌（HOB）是能利用氧气氧化氢气供能以固定二氧化碳进行自养生长的一类细菌,但是目前对能够固氮的HOB研究甚少.在自然界中部分HOB常作为植物根际促生细菌（PGPR）存在,而固氮是可能的促生机制,有望从功能菌群中得到更多的固氮HOB,是否存在氢自养且可固氮的沙雷氏菌未知.从固氮氢氧化混合菌群中分离出一株产色素的固氮菌NF-HOB1,经16S rRNA基因测序鉴定为粘质沙雷氏菌（Serratia marcescens）(GenBank:OQ625884),通过碳源或氮源限制培养实验验证其具有异养固氮生长、氢自养固碳生长能力,氢气氧化速率为0.187 5 mmol/d.聚合酶链式反应（PCR）扩增发现其质粒DNA编码固氮酶铁蛋白结构基因nifH,基因组编码种特异性的核酮糖-1,5-二磷酸羧化酶（Rubisco）和氢化酶3的结构基因.基因组框架图测序进一步揭示了菌株的基因组特征,基因组长4 919 531 bp,蛋白编码基因4 778个.注释到氢化酶2、碳酸酐酶、GlnK型PII蛋白等,提示存在二氧化碳浓缩机制和以NtrB-GlnK-amtB/nifA为特征的全局氮调控机制.基因本体论...     

含氧水溶液中δ-MnO2对非晶态Cr（OH）3的化学氧化：影响因素和作用机理

对六价铬污染水体和土壤修复常采用化学还原方法,但是当前研究对还原产物非晶态Cr（OH）₃的再氧化过程以及环境酸碱性、有机质等因素对该过程的影响仍有较多分歧.本研究通过批试验,观测了含氧水溶液体系中非晶态Cr（OH）₃的长期稳定性及pH和溶解性有机质（Dissolved organic matter,DOM）对δ-MnO₂氧化非晶态Cr（OH）₃的影响.研究结果表明,在含氧水溶液中,Cr（OH）₃具有较好的长期稳定性;δ-MnO₂会显著增大Cr（OH）₃的氧化量,Cr（Ⅵ）生成量从0.03mg·L^-1增大为0.83 mg·L^-1.环境酸碱性可显著影响δ-MnO₂对Cr（OH）₃的氧化行为,碱性条件下Cr（Ⅵ）生成量更大.当pH=8,反应365 d时,总Cr（Ⅵ）浓度可达0.83 mg·L^-1; pH=6时,反应365 d时,总C...     

机械混合法制备TiO2/g-C3N4复合材料及其光催化降解双酚A的性能

本工作采用机械混合方法,将TiO₂纳米颗粒与不同质量的g-C₃N₄复合,制备了一系列具有不同g-C₃N₄含量的TiO₂/g-C₃N₄复合材料.运用X射线粉末衍射（XRD）、X射线光电子能谱（XPS）、拉曼光谱（Raman）、比表面积分析仪（BET）、扫描电镜（SEM）和透射电镜（TEM）对材料的化学组成和形貌特征进行了表征.比较了g-C₃N₄、TiO₂和一系列TiO₂/g-C₃N₄在可见光驱动下对水中双酚A（BPA）的降解效率和矿化能力差异,发现TiO₂/g-C₃N₄的光催化活性显著高于g-C₃N₄和TiO₂,其中以TiO₂/g-C...     

Fe3O4/MoS2强化过氧化单硫酸盐活化去除2,4-二氯苯氧乙酸

以MoS₂为载体,通过水热法合成Fe₃O₄/MoS₂催化剂,采用X射线衍射、透射电子显微镜和X射线光电子能谱分析对材料进行表征,研究了Fe₃O₄/MoS₂/PMS体系中2,4-二氯苯氧基乙酸（2,4-D）的降解效率并探究了其反应机理.结果表明,以Fe₃O₄、MoS₂和Fe₃O₄/MoS₂为催化剂,30 min内2,4-D的去除率分别为31%、 20%和89%.表征结果发现,在MoS₂的存在下,Fe₃O₄表面的Fe（Ⅲ）还原为Fe（Ⅱ）,Mo（Ⅳ）被氧化为Mo（Ⅵ）,Fe₃O₄和MoS₂间的协同作用加强了PMS分解,提高了2,4-D去除效率.自由基淬灭实验表明,·OH、 SO<...     

土壤环境中四环素抗性基因向病原菌的转移研究

抗生素抗性基因（Antibiotic resistance genes,ARGs）已被公认为环境中的新型污染物,水平基因转移是ARGs传播与扩散的主要途径,纯培养体系下ARGs的水平基因转移（Horizontal gene transfer,HGT）已经多有报道,HGT的分子机制也已被充分挖掘。然而,环境中的ARGs在自然条件下是否能够转移到人类致病菌中目前仍然未知。为了探究沙门氏菌是否能够在自然条件下从施肥土壤中获得ARGs并在土壤中长期存活,将含有大量四环素敏感型沙门氏菌的粪肥施入3种土壤,并对土壤进行淹水或不淹水处理,90 d后分离四环素抗性沙门氏菌。结果表明,沙门氏菌未通过HGT获得四环素抗性基因并在土壤中长期存活。从红壤中分离到3株具有四环素抗性的疑似沙门氏菌,经过生理生化和16S测序鉴定确定它们均为产H2S的大肠杆菌,经HT-q PCR检测,它们均携带多种ARGs。对其中携带ARGs种类最多的T2菌株进行全基因组测序与分析,结果表明T2携带了两个长度分别为40.48 kb的IncX1型和93.31kb的IncY型质粒,15个基因岛,与COG数据库比对得到了3 807个注释基...     

睾丸酮丛毛单胞菌teiR基因插入失活突变体构建及降解特性分析半

睾丸酮丛毛单胞菌(Comamonas testosteroni)是革兰氏阴性菌,能够以各种类固醇化合物作为唯一碳源和能源,生物信息学分析发现睾丸酮丛毛单胞菌teiR基因编码蛋白属于LuxR-type转录调控蛋白.利用同源重组原理构建teiR基因插入失活突变体C. mut,初步研究TteiR基因在类同醇代谢途径中的作用,以及对睾丸酮丛毛单胞菌关键降解酶3a-HSD/CR的表达影响.结果发现,teiR基因插入失活突变体C.mut在LB培养基中的生长速率不受影响,突变体C.mut抑制了teiR基因和关键降解酶3a-HSD/CR的表达,同时突变体C. mut丧失了以睾丸酮作为碳源进行生长的能力.结果表明teiR基因调节睾丸酮丛毛单胞菌类因醇代谢,同时teiR基因表达对3a-HSD/CR基因的表达是必需的.图7参14     

土壤中耐砷细菌的筛选和砷还原基因多样性分析

采用琼脂平板培养法从湖南富砷土壤中筛选出43株耐砷细菌。16SrRNA序列分析结果表明所筛选菌分属于四个门：Actinobacteria、Proteobacteria、Firmicutes、Bacteroidetes,其中71．1％为革兰氏阳性菌。通过PCR和克隆测序等方法检测耐砷菌的砷还原相关基因（arrA、arsC、arsB／ACR3）及其基因多样性。检测结果显示：43株菌中,6．9％含异化砷还原基因arrA,30．2％含细胞质砷还原基因arsC,27．9％含As（Ⅲ）运载蛋白基因arsB／ACR3,这些基因在细菌中的出现频率较低。通过Mega软件构建系统发育树发现arrA基因的多样性可能受一定的地域差异影响,arsC基因在一些菌株中存在着基因水平转移现象,同时表明a变形菌可能更倾向于拥有Acr3型As（Ⅲ）载体蛋白,而arsB则多出现在芽孢杆菌中。     

奥奈达希瓦氏菌(Shewanella oneidensis) MR-1对氟西汀降解过程的转录组及功能基因分析

该文研究了厌氧条件下奥奈达希瓦氏菌(Shewanella oneidensis)MR-1对氟西汀的降解性能,并从转录组学分析遗传分子代谢机制。结果表明,Shewanella oneidensis MR-1在厌氧条件下可有效降解体系中93.12%的氟西汀,降解速率达0.94 mg·L^-1·h^-1。采用Illumina高通量测序平台对降解氟西汀后的细菌与对照组细菌进行测序,通过基因本体数据库(GO)和京都基因与基因组百科全书数据库(KEGG)富集分析,结合筛选的高表达高上调的差异表达基因,得到了耐受和降解氟西汀的功能基因,其中包膜应激反应膜蛋白基因、ABC转运蛋白基因、噬菌体休克蛋白PspA基因、氧化应激防御蛋白基因等在Shewanella oneidensis MR-1对环境的耐受中起重要作用;细胞色素C基因、硝基还原酶NfsB基因、乳酸利用蛋白基因等在氟西汀的降解转化中起关键作用。该研究从转录组水平分析了氟西汀的降解机制,可为Shewanella oneidensis MR-1在环境修复中的应用提供参考依据。     

宝鸡市秋季清洁和污染时段水溶性离子污染特征及来源解析

为探究宝鸡市秋季大气PM_2.5中水溶性离子的污染特征及来源,于2019年10月15日至11月14日分别对宝鸡市监测站、文理学院和陈仓区环保局的3个站点进行PM_2.5样品采集,通过离子色谱仪得到水溶性离子质量浓度,分析了3个站点水溶性离子在清洁时段和污染时段的变化特征及来源.结果表明,三站点PM_2.5的质量浓度陈仓区环保局>文理学院>宝鸡市监测站.清洁时段和污染时段PM_2.5平均质量浓度分别为40.0μg·m^-3和100.1μg·m^-3,水溶性离子平均质量浓度分别为（13.7±7.7）μg·m^-3和（57.8±15.0）μg·m^-3.污染时段NO₃-/SO₄2-值是清洁时段的1.6—1.8倍.污染越重,SNA（NO₃-、SO₄2-和NH₄⁺）质量浓度越大,占总水溶性离子和P...     

Retention of 137cesium in acid sulphate soils of South Central Thailand

Adsorption and desorption of ¹³⁷Cs by acid sulphate soils from the Nakhon Nayok province, South Central Plain of Thailand located near the Ongkarak Nuclear Research Center (ONRC) were investigated using a batch equilibration technique. The influence of added limestone (12 and 18 tons ha^-1) on ¹³⁷Cs adsorption-desorption was studied. Based on Freundlich isotherms, both adsorption and desorption of ¹³⁷Cs were nonlinear. A large portion (98.26-99.97%) of added ¹³⁷Cs (3.7 × 10³-7.03 × 10⁵ Bq l^-1) was sorbed by the soils with or without added lime. The higher lime treatments, however, favoured stronger adsorption of ¹³⁷Cs as compared with soil with no lime, which was supported by higher K_ads values. The addition of lime, the cation exchange capacity and pH of the soil increased and hence favoured the stronger adsorption of ¹³⁷Cs. Acid sulphate soils with a high clay content, medium to high organic matter, high CEC, and predominant clay types consisting of a mixture of illite, kaolinite, and montmorillonite were the main soil factors contributing to the high ¹³⁷Cs adsorption capacity. Competing cations such as NH₄⁺, K⁺, Na⁺, Ca²⁺, and Mg²⁺ had little influence on ¹³⁷Cs adsorption as compared with liming, where a significant positive correlation between K_ads and soil pH was observed. The ¹³⁷Cs adsorption-desorption characteristics of the acid sulphate soils studied exhibited a very strong irreversible sorption pattern. Only a small portion (0.09-0.58%) of ¹³⁷Cs adsorbed at the highest added initial ¹³⁷Cs concentration was desorbed by four successive soil extractions. Results clearly demonstrated that Nakhon Nayok province acid sulphate soils have a high ¹³⁷Cs adsorption capacity, which limits the ¹³⁷Cs bioavailability.     

δ15N-stable isotope analysis of NHx: An overview on analytical measurements,source sampling and its source apportionment

• Challenges in sampling of NH₃ sources for d¹⁵N analysis are highlighted. • Uncertainties in the isotope-based source apportionment of NH₃ and NH₄⁺ are outlined. • Characterizing dynamic isotopic fractionation may reduce uncertainties of NH_x science. Agricultural sources and non-agricultural emissions contribute to gaseous ammonia (NH₃) that plays a vital role in severe haze formation. Qualitative and quantitative contributions of these sources to ambient PM_2.5 (particulate matter with an aerodynamic equivalent diameter below 2.5 µm) concentrations remains uncertain. Stable nitrogen isotopic composition (δ¹⁵N) of NH₃ and NH₄⁺ (δ¹⁵N(NH₃) and δ¹⁵N(NH₄⁺), respectively) can yield valuable information about its sources and associated processes. This review provides an overview of the recent progress in analytical techniques for δ¹⁵N(NH₃) and δ¹⁵N(NH₄⁺) measurement, sampling of atmospheric NH₃ and NH₄⁺ in the ambient air and their sources signature (e.g., agricultural vs. fossil fuel), and isotope-based source apportionment of NH₃ in urban atmosphere. This study highlights that collecting sample that are fully representative of emission sources remains a challenge in fingerprinting δ¹⁵N(NH₃) values of NH₃ emission sources. Furthermore, isotopic fractionation during NH₃ gas-to-particle conversion under varying ambient field conditions (e.g., relative humidity, particle pH, temperature) remains unclear, which indicates more field and laboratory studies to validate theoretically predicted isotopic fractionation are required. Thus, this study concludes that lack of refined δ¹⁵N(NH₃) fingerprints and full understanding of isotopic fractionation during aerosol formation in a laboratory and field conditions is a limitation for isotope-based source apportionment of NH₃. More experimental work (in chamber studies) and theoretical estimations in combinations of field verification are necessary in characterizing isotopic fractionation under various environmental and atmospheric neutralization conditions, which would help to better interpret isotopic data and our understanding on NH_x (NH₃ + NH₄⁺) dynamics in the atmosphere.     

Decoding and quantitative detection of antibiotics by a luminescent mixed-lanthanide-organic framework

● A series of mixed-LOFs and portable LOF-fibers were synthesized. ● LOF-S3 was selected as a luminescent sensor for antibiotics. ● Mixed-LOF was capable of decoding antibiotics by emission intensity ratios. ● Linear relationship between antibiotic concentration and I545nm/I618nm was observed. Due to the potential risk of antibiotics to the environment, the development of inexpensive, simple, and reliable antibiotic detection methods is significant but also faces challenges. In this work, several lanthanide-organic frameworks (LOFs), constructed from lanthanide ions (Eu³⁺ and/or Tb³⁺) and 1,3,5-benzene-tricarboxylic acid (BTC), were synthesized by solvothermal method. LOF-S3 with comparable emission peaks of ⁵D₄ → ⁷F₅ (Tb³⁺, 545 nm) and ⁵D₀ → ⁷F₂ (Eu³⁺, 618 nm) was selected as a luminescent sensor. In this system, the highly efficient energy transferred from the organic linker to lanthanide ions and from Tb³⁺ to Eu³⁺ occurs. LOF-S3 sensor was capable of decoding antibiotics by distinguishable emission intensity ratios. Therefore, a two-dimensional decoded map of antibiotics was established. The linear relationship between antibiotic concentration and emission intensity ratio indicated the quantitative determination of antibiotics was feasible. As a typical analyte, the response mechanism of nalidixic acid (NA) was investigated in detail. The competition of NA and BTC for UV light absorption, as well as the binding propensity of NA and Tb, affected the organic linkers-to-lanthanide ions and Tb-to-Eu energy transfer, resulting in the change of fluorescence intensity ratio. The self-calibrating mixed-LOF sensor overcame the uncontrollable errors of the traditional absolute emission intensity method and generated stable luminescent signals in multiple cycles. Furthermore, the integration of LOF-S3 with polymer fibers enabled the formation of a LOF-polymer fibrous composite with fluorescence detection capability, which is a promising portable sensor for practical applications.     

Enhanced activation of peroxymonosulfate by CNT-TiO2 under UV-light assistance for efficient degradation of organic pollutants

CNT-TiO₂ composite is used to activate PMS under UV-light assistance. Superior performance is due to the enhanced electron-transfer ability of CNT. SO₄•⁻, •OH and ¹O₂ play key roles in the degradation of organic pollutants. In this work, a UV-light assisted peroxymonosulfate (PMS) activation system was constructed with the composite catalyst of multi-walled carbon nanotubes (CNT) - titanium dioxide (TiO₂). Under the UV light irradiation, the photoinduced electrons generated from TiO₂ could be continuously transferred to CNT for the activation of PMS to improve the catalytic performance of organic pollutant degradation. Meanwhile, the separation of photoinduced electron-hole pairs could enhance the photocatalysis efficiency. The electron spin resonance spectroscopy (EPR) and quenching experiments confirmed the generation of sulfate radical (SO₄•⁻), hydroxyl radical (•OH) and singlet oxygen (¹O₂) in the UV/PMS/20%CNT-TiO₂ system. Almost 100% phenol degradation was observed within 20 min UV-light irradiation. The kinetic reaction rate constant of the UV/PMS/20%CNT-TiO₂ system (0.18 min⁻¹) was 23.7 times higher than that of the PMS/Co₃O₄ system (0.0076 min⁻¹). This higher catalytic performance was ascribed to the introduction of photoinduced electrons, which could enhance the activation of PMS by the transfer of electrons in the UV/PMS/CNT-TiO₂ system.     

Chemical reclamation of crude-oil-inundated soils from Niger Delta, Nigeria

Crude-oil-inundated soils were collected from the Agbada oil field in the Niger Delta region of Nigeria 2 months after the recorded incidence of oil spillage. The soils were taken on the second day of reconnaissance from three replicate quadrats, at surface (0-15 cm) and subsurface (15-30 cm) depths, using the grid sampling technique. The total extractable hydrocarbon content (THC) of the polluted soils ranged from 1.24 × 10² to 3.86 × 10⁴ mg/kg at surface and subsurface depths (no overlap in standard errors at a 95% confidence level). Greenhouse trials for possible reclamation were later carried out using 10-100 g of (NH₄)₂SO₄, KH₂PO₄ and KCl (NPK) fertilizer as nutrient supplements. Nitrogen as NO₃-N and potassium were optimally enhanced at 2% (w/w) and 3% (w/w) of the NPK supplementation, respectively. Phosphorus, which was inherently more enhanced in the soils than the other nutrients, maintained the same level of impact after treatment with 20 g of NPK fertilizer. Total organic carbon (%TOC), total organic matter (%TOM), pH, and percentage moisture content all provided evidence of enhanced mineralization in the fertilizer-treated soils. If reclamation of the crude-oil-inundated soils is construed as the return to normal levels of metabolic activities of the soils, then the application of the inorganic fertilizers at such prescribed levels would duly accelerate the remediation process. However, this would be limited to levels of pollution empirically defined by such THC values obtained in this study.     

The size distribution of airborne bacteria and human pathogenic bacteria in a commercial composting plant

•Bacterial concentrations from eight stages were 10⁴–10⁵copies/m³. •Diameter influenced clustering of bacterial and HPB lineages. •Dg of 8 HPB ranged from 2.42 to 5.09 μm in composting areas. •Dg of 8 HPB ranged from 3.70 to 8.96 μm in packaging areas. •HPB had high concentrations and small sizes in composting areas. Composting plants are regarded as one of the important sources of environmental bioaerosols. However, limitations in the size distribution of airborne bacteria have prevented our comprehensive understanding of their risk to human health and their dispersal behavior. In this study, different sizes of airborne bacteria were collected using an eight-stage impactor from a full-scale composting facility. Size-related abundance and communities of airborne bacteria as well as human pathogenic bacteria (HPB) were investigated using 16S rRNA gene sequencing coupled with droplet digital PCR. Our results indicate that the bacterial concentrations from the eight stages were approximately 10⁴–10⁵copies/m³. Although no statistical correlation was detected between the particle size and the Shannon index, the influence of size on bacterial lineages was observed in both composting and packaging areas. For airborne bacteria from different stages, the dominant phyla were Firmicutes, Proteobacteria, and Actinobacteria, and the dominant genera was Bacillus. Seven out of eight HPB with a small geometric mean aerodynamic diameter had a high concentration in composting areas. Based on diameters of 2.42 to 5.09 μm, most HPB in the composting areas were expected to be deposited on the bronchus and secondary bronchus. However, in the packaging areas, the deposition of HPB (diameters 3.70 to 8.96 μm) occurred in the upper part of the respiratory tract. Our results on the size distribution, abundance, and diversity of these bacteria offer important information for the systematic evaluation of bacterial pathogenicity and the potential health impacts on workers in composting plants and the surrounding residents.     

Degradation of bisphenol A by microorganisms immobilized on polyvinyl alcohol microspheres

In this study, microorganisms （named B111） were immobilized on polyvinyl alcohol microspheres prepared by the inverse suspension crosslinked method. The biodegradation of bisphenol A （BPA） and 4-hydro- xybenzaldehyde, a degradation product of BPA, by free and immobilized B lll was investigated. The BPA degradation studies were carried out at initial BPA concentrations ranging from 25 to 150 mg·L^-1. The affinity constant Ks and maximum degradation rate Rmax were 98.3 mg·L^-1 and 19.7mg·mg^-1VSS·d^-1 for free B111, as well as 87.2mg·L^-1 and 21.1mg·mg^-1VSS·d^-1 for immobilized B 111, respectively. 16S rDNA gene sequence analyses confirmed that the dominant genera were Pseudomonas and Brevundimonas for BPA biodegradation in microorganisms B 111.     

Abundance and distribution of ammonia-oxidizing archaea in Tibetan and Yunnan plateau agricultural soils of China

As low oxygen and high ultraviolet （UV） exposure might significantly affect the microbial existence in plateau, it could lead to a specialized microbial community. To determine the abundance and distribution of ammonia-oxidizing archaea （AOA） in agricultural soil of plateau, seven soil samples were collected respectively from farmlands in Tibet and Yunnan cultivating the wheat, highland-barley, and colza, which are located at altitudes of 3200-3800 m above sea level. Quantitative PCR （q-PCR） and clone library targeting on amoA gene were used to quantify the abundances of AOA and ammonia-oxidizing bacteria （AOB）, and characterize the community structures of AOA in the samples. The number of AOA cells （9.34 × 10^7-2.32× 10^8 g^-1 soil） was 3.86-21.84 times greater than that of AOB cells （6.91 × 10^6-1.24 × 10^8 g^-1 soil） in most of the samples, except a soil sample cultivating highland- barley with an AOA/AOB ratio of 0.90. Based Kendall＇s correlation coefficient, no remarkable correlation between AOA abundance and the environmental factor was observed. Additionally, the diversities of AOA community were affected by total nitrogen and organic matter concentration in soils, suggesting that AOA was probably sensitive to several environmental factors, and could adjust its community structure to adapt to the environmental variation while maintaining its abundance.     

Fe2O3-CeO2-Bi2O3/γ-Al2O3 catalyst in the catalytic wet air oxidation (CWAO) of cationic red GTL under mild reaction conditions

Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃, an environmental friendly material, was investigated. The catalyst exhibited good catalytic performance in the CWAO of cationic red GTL. The apparent activation energy for the reaction was 79 kJ·mol⁻¹. HO₂· and O₂·⁻ appeared as the main reactive species in the reaction. The Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃ catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation (CWAO) of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area (BET measurement), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃ catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions (catalyst loading, degradation temperature, solution concentration and initial solution pH value) was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ·mol⁻¹. Hydroperoxy radicals (HO₂·) and superoxide radicals (O₂⁻·) appeared as the main reactive species upon the CWAO of cationic red GTL.     

Assessment of mobile and potential mobile trace elements extractability in calcareous soils using different extracting agents

• DTPA and NH₄OAc, HNO₃ and EDTA, and MgCl₂ and NH₄NO₃ had similar behavior. • In NH₄OAc, DTPA, and EDTA, the possibility of re-adsorption of trace elements is low. • CaCl₂ may be more suitable than other extracts in calcareous soils. Understanding trace elements mobility in soils, extracting agents, and their relationships with soil components, are essential for predicting their movement in soil profile and availability to plants. A laboratory study was conducted to evaluate extractability of cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), and zinc (Zn) from calcareous soils utilizing various extracting agents to be specific CaCl₂, DTPA, EDTA, HNO₃, MgCl₂, NaNO₃, NH₄NO₃, and NH₄OAc. Cluster analysis indicated that DTPA and NH₄OAc, HNO₃ and EDTA, and MgCl₂ and NH₄NO₃ extracting agents yielded comparative values, whereas NaNO₃ and CaCl₂ have shown different behavior than other extracting agents for all studied trace elements. The speciation of extracted trace elements in solutions indicated that in the CaCl₂, NaNO₃, NH₄NO₃, and MgCl₂ extracting agents most extracted Cd, Co, Ni, Zn, and part of Cu were as free ions and may be re-adsorbed on soils, leading to lower extractability, whereas, in the case of HNO₃ extracting agent, the likelihood of re-adsorption of trace elements may be little. The results of speciation of trace elements using NH₄OAc, DTPA, and EDTA extracting agents showed that Me-(Acetate)₃^–, Me-(Acetate)₂(aq), Me(DTPA)³⁻, Me(EDTA)²⁻, and MeH(EDTA)^– complexes dominated in solutions indicating that the extracted trace elements may not be re-adsorbed on soils, leading to higher extractability. The results of this study are useful for short and long-term evaluations of trace elements mobility and further environmental impacts.