Mapping out the reaction network of humin formation at the initial stage of fructose dehydration in water

The formation of humins hampers the large-scale production of 5-hydroxymethylfurfural(HMF)in biorefinery.Here,a detailed reaction network of humin formation at the initial stage of fructose-to-HMF dehydration in water is delineated by combined experimental,spectroscopic,and theoretical studies.Three bimolecular reaction pathways to build up soluble humins are demonstrated.That is,the intermolecular etherification of β-furanose at room temperature initiates the C12 path,whereas the C-C cleavage of a-furanose at 130-150℃ leads to C11 path,and that of open-chain fructose at 180℃ to C11' path.The successive intramolecular dehydrations and condensations of the as-formed bimolecular intermediates lead to three types of soluble humins.We show that the C12 path could be restrained by using HCl or AlCl_(3) catalyst,and both the C12 and C110 paths could be effectively inhibited by adding THF as a co-solvent or accelerating heating rate via microwave heating.

Effects of Fe3+ and Ca2+ on sorption of phenanthrene by Humin in karst soil,Southwest China

Humin(HM) is the main organic matter component to af fect the migration and transformation of polycyclic aromatic hydrocarbons(PAHs) in soil. The study on infl uence of the morphology change of inorganic ions on the adsorption of PAHs in soil and its organic matter is still rare at microscopic scale. In this paper, yellow soil humin(YS-HM) and lime soil humin(LS-HM) were chosen as samples, then Fe^(3+) and Ca^(2+) were added into samples to facilitate the precipitation by changing the existing conditions of ions, and the mechanism by which inorganic precipitation changed adsorption capacity of karst soil was analyzed from the microscopic scale. The results showed that the adsorption capacity of HM reduced with the inorganic precipitation increasing. The precipitation of Ca^(2+)and Fe^(3+) both reduced the adsorption capacity of YS-HM and LS-HM by 61.71% and 71.83% on average, respectively. The results of scanning electron microscope-energy dispersive spectrometry(SEM-EDS) and pore analysis showed that the HM porosity decreased after formation of Ca^(2+) and Fe^(3+) precipitation. According to the value of Freundlich parameter n, it may be because the precipitation or colloid of Ca^(2+) and Fe^(3+) fi lled micropores and covers high-energy adsorption sites of the HM. This research provides theoretical support for studying the PAHs migration and bioavailability of Calcium-rich in karst soil.

Adsorption mechanism of Cd(Ⅱ)by calcium‑modifed lignite‑derived humin in aqueous solutions

Lignite-derived humin(CHM)was extracted from raw coal in Heihe City,China,producing calcium-modifed lignite-derived humin(Ca-CHM)by Ca(OH)_(2).The physical and chemical performances of CHM and Ca-CHM were analyzed with SEM,^(13)C spectra and XPS techniques.The results show that Ca-CHM exhibited weaker aliphatic,more aromatic polar compared with CHM,which improves the adsorption capacity for Cd(Ⅱ).XPS analysis indicates that Ca(Ⅱ)has been loaded onto Ca-CHM successfully after modifcation.This batch adsorption experiments report the adsorption performance of CHM and Ca-CHM for Cd(Ⅱ).The adsorption process of CHM and Ca-CHM for Cd(Ⅱ)conform to pseudo-second-order model,which is chemical adsorption,and the adsorption data presented good fts to the Langmuir model.The maximum adsorption amount(Q_(m))of Cd(Ⅱ)onto CHM and Ca-CHM by the Langmuir model is 15.29 mg/g and 41.84 mg/g,respectively.Based on the results of SEM,^(13)C spectra,and XPS analysis,we concluded that the main adsorption mechanism of Ca-CHM on Cd(Ⅱ)was ion exchange of Cd(Ⅱ)for Ca(Ⅱ),static-adsorbed and surface complexation.Therefore,Ca(Ⅱ)can be loaded on the surface of Ca-CHM by chemical modifcation,improving the adsorption capacity of materials in aqueous solutions.

Catalytic hydrotreatment of humins into cyclic hydrocarbons over solid acid supported metal catalysts in cyclohexane

Humins are common undesirable sideproducts during many acid-catalyzed reactions in renewable biomass platform conversion. However, few studies have been reported to the efficient utilization of humins.For the first time, the selective catalytic conversion of biomass-derived humins into cyclic hydrocarbons with high conversion rate and selectivity is presented using a home-made Ru/W-P-Si-O bifunctional catalyst. The multistage polymerization structure of humins was studied through controlled experiments.Results show that the CAC bond network can be efficiently depolymerized at a mild reaction temperature of 340–380 °C, catalyzed by the cooperative catalysis of nano-Ru particles and porous strong Lewis solid acid. Particularly, 95.4% conversion of humins was achieved under the optimal condition with up to 88.3%yield of cyclic hydrocarbons. The detailed composition after liquefaction was also analyzed. This study paves the way for the efficient production of cyclic and aromatic hydrocarbons from furan-derived humin polymer through Lewis acid-catalyzed Diels–Alder reactions between furan rings.

Extraction and Characterization of Humic Acids and Humin Fractions from a Black Soil of China

Twenty-three progressive extractions were performed to study individual humic acids (Has) and humin fractions from a typical black soil (Mollisol) in Heilongjiang Province, China using elemental analysis and spectroscopic techniques. After 23 HA extractions the residue was separated into high and low organic carbon humin fractions. HA yield was the highest for the first extraction and then gradually decreased with further extractions. Organic carbon (OC) of the humin fractions accounted for 58％ of total OC even after 23 successive HA extractions. In addition, the atomic C/H ratio decreased during the course of extraction while C/O increased; the E4/E6 ratio from the UV analysis decreased with further extraction while E2/Ea increased; the band assigned to aliphatic carbon (2 930 cm-1) in the diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra gradually increased with progressive extraction; the calculated ratio of the sum of aromatic carbon peak heights to that of aliphatic carbon peak heights from DRIFTS spectra declined with extractions; and nuclear magnetic resonance (NMR) data suggested that HA aliphatic carbons increased with extractions while aromatic carbons decreased. Thus, hydrophobicity and aliphaticity of Has increased with extractions while polarity and aromaticity decreased. These data showed substantial chemical, structural, and molecular differences among the 23 Has and two humin fractions. Therefore, these results may help explain why soil and sediment humin fractions have high sorption capacity for organic contaminants.

Characteristics of humin fractions associated with inorganic minerals obtained by NaOH,and NaOH assisted with anthraquinone extraction procedures

The differences in XRD patterns, elemental compositions, FT-IR spectra and TG-DSC curves of extract residues obtained by NaOH, and NaOH assisted with anthraquinone (AQ) extraction procedures were studied. The extract residues are mainly comprised of humin fractions associated with inorganic minerals. XRD analysis shows that there is no typical peak of organic carbon because those organic humin fractions appear as a highly disordered substance. The peak of quartz is dominant. The elementary analysis shows that assistant AQ in NaOH solution can break the link of organic humic substances with inorganic minerals. And aromatization degree of humin fractions obtained by NaOH is smaller than that obtained by NaOH assisted with AQ. FT-IR analysis displays that various groups exist in those two humin fractions obtained by different extraction procedures. There are some differences in FT-IR curves between two humin fractions. TG-DSC analysis shows that thermal decomposition occurs during the heating of testing samples. By contrast, the humin fractions associated with inorganic minerals obtained by NaOH possess a higher thermal decomposition range.

Synthesis of Humin-based Carbon Quantum Dots and Luminescent Properties

The unique properties of carbon quantum dots(CQDs) make them promising materials in many fields. Herein, we present a facile method for the preparation of photo-luminescent CQDs using humins as the carbon precursor for the purpose of providing a high value-added solution for this "biomass conversion process waste". The structure of the CQDs was analyzed, and the effects of reaction temperature and time on the CQDs' fluorescence were investigated. The results showed that humins were effectively carbonized during the reaction. The fluorescence intensity of humin-based CQDs initially increased with reaction temperature and time, and subsequently decreased beyond 200℃ and 4 h. Polyaromatic structures and hydrophilic groups such as O—H, C—O, —COOH and C==O groups exist in the CQDs. The huminbased CQDs have the dimension of 3～7 nm with an average size of about 5.5 nm. The highest emission intensity of blue/cyan fluorescence light at 440 nm is achieved on the excitation with UV light at the wavelength of 330 nm.

Characterization of Soil Humin by Acid Hydrolysis

Studies were conducted to characterize soil humin by acid hydrolysis. Two humin samples collected from two different types of soil, namely chernozem and laterite, which are widespread over a vast area from the north to south of China, were hydrolyzed under reflux with 0.5M H\-2SO\-4 or 3M H\-2SO\-4 for 4 h. The results showed that \{25%-29%\} of organic carbon and \{46%-54%\} of organic nitrogen could be hydrolyzed by \{0.5M\} H\-2SO\-4; \{36%-40%\} of organic carbon and \{93%-97%\} of organic nitrogen hydrolyzed by 3M H\-2SO\-4. The C/N ratio in hydrolyzed organic matter is lower than that in soil humin and that in organic matter hydrolyzed by 3M H\-2SO\-4 is lower than that in organic matter hydrolyzed by \{0.5M\} H\-2SO\-4. The proportion of nitrogen hydrolyzed from humin is markedly larger than that from the original soil and also markedly larger than that from humic acid fraction. Only \{3%-7%\} of nitrogen in humin exists in a relatively stable form, which is not easy to hydrolyze. There is little nitrogen that occurs in the form of heterocyclic rings in humin. Incubation experiments showed that the newly formed organic matter can be hydrolyzed more easily.

Yolk-shell structure synergistic defect engineering for boosting electromagnetic wave absorption in Co_(9)S_(8)@Humins-derived carbon

Exploring new strategies to incorporate the concepts of green chemistry and defect engineering into new architectures to address the problem of severe electromagnetic wave(EMW)pollution is challenging.In this work,by using a by-product of catalytic conversion of biomass as a carbon source,we prepare two-dimensional(2D)Co_(9)S_(8)-coated humins-derived carbon nanomaterials with a yolk-shell structure.The EMW attenuation ability is finally optimized by controlling the morphology and defects of the composite material through the pyrolysis temperature.As expected,with the synergy of conductive loss/interfacial polarization and defects regulating,the composite material achieves a reflection loss(RL)value of−51.4 dB in Ku-band and the effective absorption bandwidth(EAB)can be as high as 5.92 GHz(12.08–18.00 GHz)at 1.8 mm ultra-thin coating thickness.A strong absorption capacity in the low-frequency C-band(6.4 GHz)reaches RL value of−49.9 dB and a thickness of 3.50 mm,which grants it the characteristic of convertible microwave absorption from high frequency to low frequency.Taking account of the facile synthesis and tunable absorption properties,the encouraging findings shed light on exploring waste-turned-microwave absorbents with promising practical applications.

泥炭土腐殖酸环境室内模拟试验研究

为能提供一种贴合天然环境的泥炭土腐殖酸环境,通过在冲洪积黏性土中掺入胡敏酸(Humic Acid, HA)试剂和富里酸(Fulvic Acid, FA)试剂人工制备泥炭土试样,并将试样浸泡在富里酸液中来模拟泥炭土腐殖酸环境。采用腐殖酸含量检测试验、扫描电镜(Scanning Electron Microscope, SEM)、X射线衍射(X-Ray Diffraction, XRD)、X射线荧光光谱(X-Ray Fluorescence spectroscopy, XRF)和无侧限抗压强度(qu)试验来评估模拟效果及可行性。结果表明,在pH值为6.0的浸泡液中浸泡90 d后,试样中富里酸实测质量分数超过了初始掺量,而胡敏酸的实测质量分数相较于初始掺量表现出波动性。试样中孔隙随着腐殖酸掺量的增加而逐渐发育连通,试样所含的原生矿物主要为石英和云母,主要元素为O、Si、Al和Fe。通过与天然泥炭土环境对比分析,揭示了模拟的腐殖酸环境在微观特征上与天然腐殖酸环境具有相似性。宏观力学试验结果表明,模拟试样的qu随腐殖酸掺量的增加而降低,对比分析显示模拟试样的力学性能与天然泥炭土的力学性能接近。以上结果表明,采用所提出的方法可以模拟出与天然泥炭土环境相近的泥炭土腐殖酸环境。

丙酮盐酸混合液提取土壤腐殖质组分的光谱学特征

采用丙酮盐酸混合液提取土壤胡敏酸(HA)和胡敏素(HU)组分,利用元素分析、紫外-可见漫反射光谱和红外光谱进行结构表征。元素分析表明,HA中C、H、N和S含量均高于HU,O含量低于HU。原子比分析表明HA的缩合度相对较高,分子结构相对复杂,HU的缩合度相对较低,分子结构相对简单。紫外-可见漫反射光谱分析表明,由于腐殖质(HS)的组成复杂,多种官能团互相干扰,HA和HU紫外-可见漫反射光谱无明显特征峰,吸光度值随着波长的增加呈下降趋势,且HA包含的吸光有机成分较多,化学组成较复杂。HA和HU紫外特征参数SUV254和E4/E6比较分析表明,与HU相比,HA芳香性较大,腐殖化程度较高。红外光谱分析表明,HA和HU具有相似的红外光谱,各研究对象特征吸收峰的吸收强度不同,其中开垦黑土20~40 cm和未开垦灰土18~37 cm土层HA的振动幅度较大,说明其包含的酚类化合物、含羟基化合物、脂肪族化合物和羧酸,以及含羰基的醛、酮、醚等化合物的含量较多。开垦黑土10~20 cm土层和未开垦灰土18~37 cm土层HU在各特征吸收峰振动幅度较大,说明其包含的酚类化合物、羧酸、脂肪烃和糖类化合物含量较多。红外光谱各吸收峰强度比较分析表明,开垦后黑土HA和HU酚类化合物、羟基官能团和脂肪族化合物等含量增加,而开垦后灰土HA和HU酚类化合物、羧酸和脂肪族化合物含量下降,表明开垦对黑土土壤有机质影响相对较小,并且在一定程度上增加了土壤有机质含量,而促进了灰土土壤有机质的分解。综上所述,丙酮盐酸混合液提取法为HS生物化学和生理活性的研究提供了新的技术手段,为合理利用土壤资源提供理论依据。

胡敏素-锰氧化物复合材料对铅的吸附特征研究

以矿源煤基胡敏素(Humin,HM)为基体,用不同浓度KMnO_(4)溶液制备改性胡敏素材料胡敏素-锰氧化物复合材料(HMM),考察了HMM用量、初始pH对重金属的吸附效果影响;利用吸附动力学和吸附等温线以及扫描电镜(SEM)、红外光谱(FT-IR)等对其进行表征分析,探索了HMM对重金属的吸附机理。结果表明,HM表面负载MnO_(x)后增加了HM的表面吸附位点,随KMnO_(4)浓度的升高,HMM对Pb^(2+)吸附效果略有升高,吸附动力学遵循准二级动力学模型,化学吸附占主导作用;吸附等温线符合Langumir模型方程,0.05HMM对Pb^(2+)的最大吸附量Qm为397.911 mg/g,是HM的2.5倍;通过改性提高了HM对Pb^(2+)的吸附能力以及吸附的稳定性。

金属元素Ni和V吸附作用对胡敏素结构的影响

贵州下寒武统牛蹄塘组黑色页岩富集了以Ni、V为主的伴生元素,并且富有机质,目前金属元素Ni、V与有机质的共富集机制尚不清楚,但有机质在金属离子的富集、迁移和转化的过程中具有重要作用。探究金属元素作用对有机质结构的影响有助于准确地认识有机质和金属元素的共富集机制。本文以胡敏素为研究对象,分别与Ni、V两种金属标准溶液混合后恒温振荡,通过元素组成、X射线光电子能谱(XPS)和固体核磁共振碳谱(^(13)C-NMR)由表到里揭示金属溶液作用前后胡敏素结构的变化特征。结果表明:胡敏素的元素组成以C、O为主,Ni、V两种金属溶液作用后,均造成胡敏素中O和S元素的相对含量减少,C和N元素的相对含量增加。XPS测试显示,胡敏素表面的C元素主要以芳香碳形态赋存,O元素则主要以羟基氧形态赋存;对于不同赋存形态的C元素,Ni、V金属溶液作用后对其影响趋势一致,均使芳香碳、羟基碳和羰基碳减少,主要破坏芳香碳(C-C/C-H)单键;而对于不同赋存形态的O元素,Ni金属溶液作用后则使羟基氧和羧基氧减少,使其中的富氢富氧官能团脱出,V金属溶液作用后则使羰基氧和羧基氧减少,破坏其中的羰基双键(C=O)。^(13)C-NMR测试显示,作用前后的胡敏素有机质芳香结构主要以单环或者双环结构存在,两种金属溶液均能使氧接芳碳(f^(P)_(ar))和桥接芳碳(f^(B)_(ar))中的富氧富氢官能团从芳环中脱出、胡敏素中脂链长度变短、有机碳的稳定性降低、活性有机碳含量减少以及疏水程度变小。通过对比分析表明,胡敏素对Ni、V金属元素具有一定的氧化能力,两种金属溶液作用后均能使胡敏素中C、O元素的赋存形态发生改变,Ni金属溶液主要影响脂肪碳结构,V金属溶液则主要影响芳碳结构。

上海市沪闵高架快速路大修施工期间交通组织研究

沪闵高架大修是2021年“迎七一”交通保障的重要项目之一,需在确保项目按时完工的前提下,最小化封道期间的交通不利影响。将研究对象按工程特性分为“一般路段”和“特殊节点”2类。“一般路段”所需施工时间较短,在现行日常养护10 d一周期封闭的基础上,创新性提出5 d为一周期封闭一侧、一段的方法,以减少封闭区长度;对于“特殊节点”存在长时间、连续作业的施工要求,以定量数据为支撑,制定前后翻交的精细化交通组织方案,并通过仿真分析不同阶段施工期间交通影响,提出相应施工期间交通组织的配套措施。沪闵高架快速路大修施工封道交通组织研究是对现状日常封道施工交通组织的一次创新探索,也为其他类似项目的实施提供一定借鉴。

土壤胡敏素各组分数量及结构特征初步研究

土壤胡敏素(HM)是与矿物质紧密结合的腐殖物质,具有碱不溶性及大分子结构的特性,并呈现不均一性,被认为是土壤中的惰性物质。由于HM的非溶解性和结构复杂性,目前国内外学者对于HM结构特征的研究还很少。对加入大量有机物料培养后新形成的HM数量及性质的研究尚未见报道。本研究选用风沙土、草甸土、黑土、黑土底土加玉米秸秆培养土为材料,根据Pallo分组法,将土壤HM分为铁结合胡敏素(HMi)、粘粒结合胡敏素(HMc)和不溶性胡敏素(HMr)三个组分;对自然土壤中HM各组分以及加入玉米秸秆后新形成的HM各组分的数量及结构特征进行初步研究,为丰富腐殖质化学提供基础性资料。实验结果表明:在自然土壤HM各组分中以HMr为主,其次是HMi,含量最少的是HMc。通过HMi和HMc的光学性质比较得出HMi的分子结构较简单,HMc分子结构相对较复杂,加玉米秸秆培养后新形成的HMi、HMc的分子结构比自然土壤中的简单。红外光谱结果表明,与自然土壤相比加玉米秸秆培养后新形成的HMi、HMc的脂族性最强,自然土壤中HMi、HMc的脂族性强弱顺序为:风沙土>黑土>草甸土。

胡敏素对Pb^(2+)吸附的响应面优化及机理

采用Box-Behnken响应面优化实验设计对胡敏素吸附去除水中Pb^(2+)的过程进行了优化,设定吸附时间、吸附剂用量、pH值、温度和Pb^(2+)初始浓度5个影响因素,建立了吸附率与上述因素之间的二次多项式模型,确定了最优吸附条件,对吸附过程的等温模型、热力学特性及吸附机理进行了研究.研究表明吸附剂用量、pH值、温度和Pb^(2+)初始浓度为显著因素.胡敏素对Pb^(2+)吸附的最优条件为:吸附时间85min、投加量1.2g/L、pH=4.7、温度44.5℃、Pb^(2+)初始浓度202mg/L.最优条件下,实测Pb^(2+)吸附率可达92.59%.胡敏素对Pb^(2+)的吸附符合Langmuir等温线方程,最大吸附量为170.28mg/g;计算得知胡敏素吸附Pb^(2+)的热力学状态函数ΔG^0、ΔS^0和ΔH^0分别为-29.30^-24.21k J/mol、126.70J/(mol·K)和13.59k J/mol,吸附过程为吸热过程.胡敏素表面的羰基、羟基、氨基和羧基等活性基团可以和Pb^(2+)发生配位络合作用,Ca、Na和Mg等离子与Pb^(2+)发生离子交换作用.研究结果表明,胡敏素作为一种极具潜力的绿色廉价吸附剂,可用于处理含Pb^(2+)废水.

土壤有机质级份的红外和热重特性

用红外分析(FTIR)和热失重分析法对从三种不同利用方式下的黄泥土中提取出的FA,HA及用酸性二甲基亚砜(DMSO)和HF HCl两种方法提取胡敏素的元素组成及结构特征进行分析,结果表明:胡敏素占腐殖质总碳的60—70%,FA和HA分别占10%和15%左右;不同利用方式下土壤的DMSO humin,HF humin1,HF humin2在波数2930/1640处的吸收强度比分别为1.18—1.44,0.32—0.43,0.37—0.41;DMSO humin在78—86℃和264—282℃出现了主要的失重峰,HF humin1和HF humin2的主要失重峰在333—338℃和438—458℃之间,FA和HA的主要失重峰分别在300℃和359℃左右,说明用DMSO提取的胡敏素脂肪族类物质较多,缩合程度较低;而用HF HCl提取的则含较多的芳香族类物质,缩合程度较高.

土壤粗胡敏素对铜离子的吸附作用及其影响因素

以暗棕壤为供试土壤,应用批量平衡法,研究了不同pH、离子强度、温度、Cu2+浓度和反应时间条件下,粗胡敏素(CHM)对Cu2+的吸附作用,并与相应胡敏酸(HA)的吸附作用进行了比较.结果表明:pH为2～4时,CHM对Cu2+的吸附率较低;随着pH的提高,吸附率增大;pH=7时,吸附率接近100%.随离子强度(0.01～1.00mo·lL-1)增加,CHM对Cu2+的吸附量下降,其对Cu2+的吸附包括电性和专性吸附2种作用.随温度(25～45℃)的升高和Cu2+浓度(0～1000mg·L-1)的增加,CHM对Cu2+的吸附量增加,并与Langmuir方程拟合程度最好,25℃和45℃时的最大吸附量分别为12.61mg·g-1和14.31mg·g-1·CHM对Cu2+的吸附动力学过程可划分为快速(0～120min)和慢速(120～1440min)反应阶段,抛物线扩散方程拟合效果最好.与HA相比,CHM对Cu2+的吸附规律与HA相似,但其吸附量低于HA;表观热力学参数(ΔG、ΔH、ΔS)表明,CHM对Cu2+的吸附是自发、吸热和熵增加的过程,Cu2+在CHM上的吸附力大、活动性小、不易解吸,而在HA上的吸附力小、活动性大、容易解吸;活化能(E)和活化热力学参数(ΔG#、ΔH#、ΔS#)表明,CHM对Cu2+吸附所需能量多、活化熵高、吸附速率小,而HA对Cu2+吸附所需能量少、活化熵低、吸附速率大.

长期施用有机肥对黑土胡敏素结构特征的影响-固态^(13)C核磁共振研究

【目的】研究连作玉米农田长期施用有机肥(猪粪)对黑土胡敏素(HM)结构特征的影响,比较不同施肥量和施肥年限间的差异,为阐明HM在土壤肥力上的作用提供理论依据。【方法】以1980年建立的国家黑土肥力与肥料效益监测基地的长期肥料试验为平台,采集定位12年和25年的3个试验处理(①不施肥CK;②施低量有机肥,施猪粪30t·hm-2·a-1;③施高量有机肥,施猪粪60t·hm-2·a-1)土样,在NaOH-Na4P2O7分离和HF-HCl脱灰处理的基础上,应用固态13C交叉极化魔角自旋核磁共振(13CCPMAS NMR)方法对HM进行结构表征。【结果】与不施肥相比,施用有机肥后HM的有机碳含量增加,烷基C比例增加,烷氧C和芳香C比例下降,烷基C/烷氧C、脂族C/芳香C和疏水C/亲水C比值增加,上述规律性随有机肥施用量的提高和施用年限的延长表现得更加明显。不施肥处理随年限延长,HM的有机碳含量降低,而烷基C、烷氧C和芳香C比例以及烷基C/烷氧C、脂族C/芳香C和疏水C/亲水C比值均表现出与施肥处理相同的变化规律,但其变化幅度小于施肥处理。【结论】长期施用有机肥使土壤HM的结构向着烷基化和疏水性程度增加的方向发展,这对于土壤肥力的保持是有利的。

甲磺隆在土壤腐殖物质中结合残留的动态变化

土壤中14 C 甲磺隆的可提取态残留物随时间延长不断降低 ,而其结合态残留率第 2 8天达最高 .14 C 甲磺隆结合态残留物在土壤腐殖物质中的分布是 :富啡酸 胡敏素 >胡敏酸 .在处理最初 2 8天 ,富啡酸中14 C 甲磺隆结合态残留物不断增大 ,随后减少 ;胡敏素中的结合态残留量在 2 8— 2 2 4天变化不大 .14 C残留物在不同土壤之间的结合及其分布都是有差异的 ,与土壤pH值。