染料高效吸附菌Penicillium oxalicum表面特征解析

本研究利用Zeta电位和酸碱滴定技术对Penicillium oxalicum菌体的表面性质进行了表征，应用线性规划法求解出菌体表面在表面反应中起主要作用的4种基团酸度常数分别为4．O、7．0,8．8和10．0。与文献中数据的比较推断这些基团为羧基、磷酸基团、胺基及羟基，菌体的FTIR红外光谱解析初步验证了这一结果，上述结论为进一步研究生物吸附中菌体与吸附质之间的作用提供了必要的依据。     

锑的成矿构造地球化学特性研究

概括了锑元素在地球及地壳各圈层中的丰度及分配特性 ,总结了锑的一般矿物地球化学特征及迁移富集形式 ,最后对锑元素成矿构造地球化学特性进行了探讨。     

稻田硝酸盐异化还原成铵细菌群落结构的垂向分布特性

硝酸盐异化还原成铵（Dissimilatory nitrate reduction to ammonium，DNRA）过程，可将土壤中的NO₃^-/NO₂^-还原成NH₄⁺-N以被作物吸收利用，有助于土壤中氮素的保存.选择位于广东韶关市和吉林安图县的两块稻田为研究对象，通过分子生物学方法和高通量测序技术，深入探究了两种稻田土壤（0~1 m）中DNRA细菌丰度和群落结构的垂向分布特性.结果显示：两种稻田土壤中DNRA细菌更多的存在于表层土壤（0~20 cm）中，丰度最低值均出现在深层土壤（90~100 cm）中，且表层样品群落结构的多样性大于深层样品；两个稻田样品间的群落结构体现出明显的空间异质性，安图稻田样品DNRA细菌的丰度和群落结构多样性均大于韶关稻田样品；其中，相对丰度较高的Anaeromyxobacter（28.67%）、Caldimicrobium（19.49%）、Nitrospira（10.90%）和Chthoniobacter（9.15%）是两个稻田中DNRA细菌群落组成中的关键菌属.相关性分析表明，总硫（TS）、有机质（TOM）、含水率（MC）、碳氮比（C/N）与DNRA细菌丰度之间均有显著正相关性（p<0.01，n=20），偏碱性、有机质丰富、氮源缺乏、碳源丰富且C/N较高的环境及适宜的含水率是稻田垂向生态系统中DNRA细菌适宜的生存环境.     

黄淮海平原主要土类中硝态氮水平运移规律

对黄淮海平源的主要土壤类型（黄潮土和风沙土）中硝态氮水平运移规律进行了研究。结果表明：硝态氮水平运移速率随供试示踪剂源的距离增加而迅速减小,其变化趋势呈幂函数关系。由于各土层的土壤性质不同,所以硝态氮的运移风线发生差异,但总的趋势是离示踪剂源20cm距离内,硝态氮的水平运移速率主要由硝态氮的浓度梯度和水势梯度控制,而在20cm以后趋于平稳,则主要由土壤的基质势起作用。硝态氮水平运移速率随土壤含水量的增大而升高,并呈指数曲线变化。硝态氮水平运移的浓度受非饱和土壤水扩散率的影响,并随非饱和土壤水扩散率的升高而呈对数曲线下降。     

Brilliant red X-3B uptake by a novel polycyclodextrin-modified magnetic cationic hydrogel: Performance, kinetics and mechanism

A novel polycyclodextrin-modified magnetic cationic hydrogel (PCD-MCH) was developed and its performance, kinetics and mechanism for the removal of reactive brilliant red X-3B (X-3B) were studied. The results showed that the zeta-potential of PCD-MCH was 32.8 to 16.7 mV at pH 3.0–10.5. The maximum X-3B adsorption capacity of PCD-MCH was 2792.3 mg/g. The adsorption kinetics could be well-described by the Weber–Morris model and the homogeneous surface diffusion model (HSDM). Diffusion stages corresponding to surface or film diffusion, intra-particle or wide mesopore diffusion, and narrow mesopore/micropore diffusion occurred at 0–120, 120–480 and 480–1200 min, respectively. The latter two diffusion stages were rate-controlling for X-3B adsorption kinetics. At the initial X-3B concentration of 600 mg/L, the diffusion coefficient (D_s) and external mass transfer coefficient in the liquid phase (k_F) were 3 × 10^?11 cm²/min and 4.68 × 10^?6 cm/min, respectively. X-3B approaching the center of PCD-MCH particles could be observed at 360 min. At the end of the third diffusion stage, the C_p at q/q_e = 0 was 45.20 mg/L, which was close to the homogeneous C_p value of 46 mg/L along the radius of PCD-MCH particles. At pH 3.0–10.0, PCD-MCH showed stable X-3B adsorption capacities. After five regeneration-reuse cycles, the residual adsorption capacity of regenerated PCD-MCH was higher than 892.7 mg/g. The corresponding adsorption mechanism was identified as involving electrostatic interactions, cyclodextrin cavities and hydrogen bonds, of which cyclodextrin cavities showed prominent capture performance towards dye molecules through the formation of inclusion complexes.     

一株耐镉伯克氏菌的分离鉴定及其对镉的吸收转运特性

农田土壤镉（Cd）污染日益加剧,严重威胁着农村生态安全与居民身体健康,而微生物修复被认为是一种行之有效的Cd污染土壤原位修复方法.为了给Cd污染土壤微生物修复提供功能菌株,采取平板划线从Cd污染土壤中分离纯化得到一株高耐性耐Cd菌株B-6,通过生理生化试验及16S rDNA对其进行了鉴定,并研究了菌株对Cd²⁺的吸收转运特性.经鉴定,高耐性耐Cd菌株B-6为伯克霍尔德菌属（Burkholderia cepacia）,其对Cd²⁺的耐受阈值为850 mg·L^-1.通过单因素优化培养发现,菌株B-6对Cd²⁺的吸收量随着培养温度的增加先增大后减小;随着培养液初始pH值的增大先增大后减小,同时发现菌株B-6能够有效调控系统的终点pH值;随着转速的增大先增大后减小.当初始浓度为400 mg·L^-1,培养温度为30℃,培养液初始pH值为5.0,转速为120 r·min^-1,培养时间为72 h时,菌株B-6对Cd²⁺的吸收效果最佳,达到51 mg·g^-1.通过分析亚细胞组分Cd²⁺含量发现,Cd²⁺被菌体吸收后主要赋存于细胞壁.     

Electronic-property dependent interactions between tetracycline and graphene nanomaterials in aqueous solution

Understanding the interactions between graphene nanomaterials(GNMs) and antibiotics in aqueous solution is critical to both the engineering applications of GNMs and the assessment of their potential impact on the fate and transport of antibiotics in the aquatic environment. In this study, adsorption of one common antibiotic, tetracycline, by graphene oxide(GO) and reduced graphene oxide(RGO) was examined with multi-walled carbon nanotubes(MWCNTs) and graphite as comparison. The results showed that the tetracycline adsorption capacity by the four selected carbonaceous materials on the unit mass basis followed an order of GO RGO MWCNTs graphite. Upon normalization by surface area,graphite, RGO and MWCNTs had almost the same high tetracycline adsorption affinity while GO exhibited the lowest. We proposed π-electron-property dependent interaction mechanisms to explain the observed different adsorption behaviors. Density functional theory(DFT) calculations suggested that the oxygen-containing functional groups on GO surface reduced its π-electron-donating ability, and thus decreased the π-based interactions between tetracycline and GO surface. Comparison of adsorption efficiency at different p H indicated that electrostatic interaction also played an important role in tetracycline-GO interactions. Site energy analysis confirmed a highly heterogeneous distribution of the binding sites and strong tetracycline binding affinity of GO surface.     

MO_x-CeO_2/HZSM-5催化剂催化氧化含氯挥发性有机物研究

采用浸渍法制备了不同过渡金属掺杂的MOx-CeO2/HZSM-5（M分别表示Cr、Mn、Fe、Co、Ni和Cu）催化剂,研究了各催化剂对1,2-二氯乙烷（DCE）的催化降解性能.结果表明,过渡金属掺杂后,MOx-12%CeO2/HZSM-5催化剂催化氧化1,2-二氯乙烷（DCE）的活性明显提高.各催化剂（记为M-CeO...     

氮肥与DCD配施对棚室黄瓜土壤NH3挥发损失及N2O排放的影响

以传统水氮管理为对照,进行了优化水氮管理条件下氮肥与DCD配施对大棚黄瓜土壤氨挥发损失及氧化亚氮排放的影响研究.试验结果表明,与传统水氮管理相比,优化水氮管理减少了氮肥用量及灌水量,但黄瓜产量并没有降低.各水氮处理的NH3挥发速率峰值出现在施肥灌水后的第3d,添加DCD的各优化水氮处理与传统水氮处理相比,土壤氨挥发累积量分别减少55.97%、43.68%、66.47%,4次追肥后W2N2+DCD、W2N3+DCD和W2N4+DCD的氨挥发速率峰值与累积量变化范围较小.不同水氮处理的N2O排放通量的峰值均出现在施肥灌水后的第4d,各追肥时期W2N2+DCD、W2N3+DCD和W2N4+DCD处理,土壤N2O排放通量峰值与N2O累计排放量均显著低于传统水氮处理W1N1,并且3个处理之间不存在显著差异,充分表明优化水氮管理中将氮肥与DCD配施对减少N2O排放起到了显著作用.     

Antimony(V) removal from water by iron-zirconium bimetal oxide: Performance and mechanism

A Fe-Zr binary oxide adsorbent has been successfully synthesized using a co-precipitation method. It showed a better performance for antimonate (Sb(V)) removal than zirconium oxide or amorphous ferric oxide. The experimental results showed that the Fe-Zr adsorbent has a capacity of 51 mg/g at an initial Sb(V) concentration of 10 mg/L at pH 7.0. Sb(V) adsorption on the Fe-Zr bimetal oxide is normally an endothermic reaction. Most of the Sb(V) adsorption took place within 3 hr and followed a pseudo second-order rate law. Co-existing anions such as SO₄^2-, NO₃^- and Cl^- had no considerable effects on the Sb(V) removal; PO₃^4- had an inhibitory effect to some extent at high concentration; while CO_₃^2- and SiO₄^4- showed significant inhibitory effects when they existed in high concentrations. The mechanism of Sb(V) adsorption on the adsorbent was investigated using a combination of zeta potential measurements, XPS, Raman, FT-IR observations and SO₄^2- release determination. The ionic strength dependence and zeta potential measurements indicated that inner-sphere surface complexes were formed after Sb(V) adsorption. Raman and XPS observations demonstrated that both Fe-OH and Zr-OH sites at the surface of the Fe-Zr adsorbent play important roles in the Sb(V) adsorption. FT-IR characterization and SO₄^2- release determination further demonstrated that the exchange of SO₄^2- with Sb(V) also could promote the adsorption process. In conclusion, this adsorbent showed high potential for future application in Sb(V) removal from contaminated water.