Degradation of kanamycin from production wastewater with high-concentration organic matrices by hydrothermal treatment

It is known that many kinds of fermentative antibiotics can be removed by temperature-enhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics. However, a few aminoglycosides are hard to hydrolyze below 100°C because of their stability expressed by high molecular energy gap (ΔE). Herein, removal of hard-to-hydrolyze kanamycin residue from production wastewater by hydrothermal treatment at subcritical temperatures was investigated. The results showed the reaction temperature had a significant impact on kanamycin degradation. The degradation half-life (t_1/2) was shortened by 87.17-fold when the hydrothermal treatment temperature was increased from 100°C to 180°C. The t_1/2 of kanamycin in the N₂ process was extended by 1.08-1.34-fold compared to that of the corresponding air process at reaction temperatures of 140-180°C, indicating that the reactions during hydrothermal treatment process mainly include oxidation and hydrolysis. However, the contribution of hydrolysis was calculated as 75%-98%, which showed hydrolysis played a major role during the process, providing possibilities for the removal of kanamycin from production wastewaters with high-concentration organic matrices. Five transformation products with lower antibacterial activity than kanamycin were identified using UPLC-QTOF-MS analysis. More importantly, hydrothermal treatment could remove 97.9% of antibacterial activity (kanamycin EQ, 1,109 mg/L) from actual production wastewater with COD_Cr around 100,000 mg/L. Furthermore, the methane production yield in anaerobic inhibition tests could be increased about 2.3 times by adopting the hydrothermal pretreatment. Therefore, it is concluded that hydrothermal treatment as a pretreatment technology is an efficient method for removing high-concentration hard-to-hydrolyze antibiotic residues from wastewater with high-concentration organic matrices.     

TiO2表面沉积Ag粒子及其可见光下降解含盐废水中的苯酚

为了制备可见光激发下能高效降解含盐废水中有机物的光催化剂,首次以商用TiO_2光催化剂(P25)为载体,利用吸附相反应技术一步获得了Ag沉积的可见光响应复合光催化剂.同时,通过XPS、TEM、HRTEM及紫外可见漫反射光谱图,结合多种高含盐水体系中苯酚的光催化降解过程,研究了不同Ag沉积对催化剂可见光活性的影响.结果发现,吸附平衡后P25表面富含水的吸附层可作为反应和粒子的生成场所,生成量子尺寸的Ag粒子.另外,在吸附层中生成的Ag粒子均匀分布于P25表面并与之紧密结合,并在TiO_2晶格结构中引入晶格交错结构.Ag与TiO_2的表面等离子体共振效应和晶格交错结构共同提升了催化剂的可见光响应和电荷的分离效率,增强了催化剂对苯酚的可见光催化性能.在含盐废水体系中,盐离子数量越多,催化剂在可见光下降解苯酚过程受到的干扰越大.     

一株新颖的Providencia sp.菌降解吲哚及合成靛蓝的特性研究

吲哚是一种典型的氮杂环芳烃污染物,在焦化废水和畜牧废水中大量存在.本研究从近海泥沙中分离纯化得到一株高效吲哚降解菌DCX,经16S rRNA基因序列比对分析,鉴定其为普罗维登斯菌属(Providencia sp.).该菌株能够以吲哚为唯一碳源,在28 h内将100 mg·L~(-1)吲哚完全降解.液相色谱/飞行时间-质谱联用(LC/TOF-MS)的结果表明,靛蓝、靛红、靛红酸及邻氨基苯甲酸是菌株DCX降解吲哚过程中的中间产物.此外,本研究中发现,外加营养物质可以促进菌株DCX降解吲哚,特别是加入酵母浸粉后,反应体系中会产生大量靛蓝.利用表面响应法确定菌株DCX转化吲哚合成靛蓝的最优条件为:吲哚207.49 mg·L~(-1),酵母浸粉2.9 g·L-1,接菌量4.23%(V/V),并且在最优条件下,靛蓝产率达到最高(9.90%),比初始条件提高了4.38倍.     

生物质气化费托合成制航煤生命周期评价

基于生命周期评价（LCA）,对生物质气化费托合成制航煤（Bio-Jet Fuel）工艺进行资源-环境性分析.根据副产品水蒸汽的用途研究了供热和发电两种方案,并进行了数据不确定度分析.结果显示：除EP指标外,发电方案的各环境影响指标比供热方案降低了11.7%~40.8%.相比化石航煤,生物质航煤GWP降低52.6%~71.9%,不可再生资源消耗减少84.4%~93.6%.生物质生长阶段采用不同的分配方法,资源消耗潜值差异较小,但GWP、EP环境影响负荷会产生较大差异.且生物质航煤综合性能对原料消耗率敏感性最大,变化幅度为-16.6%~+17.3%.采用不确定度分析方法对评价结果进行数据质量评估,各环境影响类型的不确定度处于5.0%~12.5%.     

Facile one-step synthesis of functionalized biochar from sustainable prolifera-green-tide source for enhanced adsorption of copper ions

The use of biochars formed by hydrothermal carbonization for the treatment of contaminated water has been greatly limited,due to their poorly developed porosity and low content of surface functional groups.Also,the most common modification routes inevitably require post-treatment processes,which are time-consuming and energy-wasting.Hence,the objective of this research was to produce a cost-effective biochar with improved performance for the treatment of heavy metal pollution through a facile one-step hydrothermal carbonization process coupled with ammonium phosphate,thiocarbamide,ammonium chloride or urea,without any posttreatment.The effects of various operational parameters,including type of modification reagent,time and temperature of hydrothermal treatment,and ratio of modification reagent to precursor during impregnation,on the copper ion adsorption were examined.The adsorption data fit the Langmuir adsorption isotherm model quite well.The maximum adsorption capacities(mg/g) of the biochars towards copper ions followed the order of 40-8 h-1.0-APBC(95.24) 140-8 h-0-BC(12.52) 140-8 h-1.0-TUBC(12.08) 140-8 h-1.0-ACBC(7.440) 140-8 h-1.0-URBC(5.277).The results indicated that biochars modified with ammonium phosphate displayed excellent adsorption performance toward copper ions,which was 7.6-fold higher than that of the pristine biochar.EDX and FT-IR analyses before and after adsorption demonstrated that the main removal mechanism involved complexation between the phosphate groups on the surface of the modified biochars and copper ions.     

不饱和季铵盐的合成及其聚合物在化工及环保领域的应用

按不饱和基团的类型对不饱和季铵盐进行了分类,并综述了其合成方法。介绍了其聚合物在含油污水处理、抗菌、纺织品、新材料等领域的应用。阐述了在不饱和季铵盐的开发及其聚合物的应用方面存在的问题。指出了今后的发展方向:应该加大科研投入,加快新型不饱和季铵盐的研发进程,特别是在主结构设计、纯度提高以及新型絮凝剂单体的多样性方面,以制备出多功能性的单体和聚合物。     

钛酸纳米管的光催化性能研究

以Ti0_2(Degussa P25)和NaOH为原料,采用水热法制备钛酸纳米管.以亚甲基蓝溶液(Methylene Blue,简称MB)为模型污染物,研究水热反应条件对所制钛酸纳米管光催化性能的影响,以及钛酸纳米管加入量、溶液pH值和MB初始浓度等光催化反应条件对钛酸纳米管光催化性能的影响.研究表明:水热反应温度为150℃,反应时间为48 h制得的钛酸纳米管对MB的光催化效率最高;钛酸纳米管的加入量、溶液pH值和MB初始浓度等光催化反应条件对钛酸纳米管的光催化性能有较大影响.     

Hydrothermal carbonization of food waste and associated packaging materials for energy source generation

Hydrothermal carbonization (HTC) is a thermal conversion technique that converts food wastes and associated packaging materials to a valuable, energy-rich resource. Food waste collected from local restaurants was carbonized over time at different temperatures (225, 250 and 275 °C) and solids concentrations to determine how process conditions influence carbonization product properties and composition. Experiments were also conducted to determine the influence of packaging material on food waste carbonization. Results indicate the majority of initial carbon remains integrated within the solid-phase at the solids concentrations and reaction temperatures evaluated. Initial solids concentration influences carbon distribution because of increased compound solubilization, while changes in reaction temperature imparted little change on carbon distribution. The presence of packaging materials significantly influences the energy content of the recovered solids. As the proportion of packaging materials increase, the energy content of recovered solids decreases because of the low energetic retention associated with the packaging materials. HTC results in net positive energy balances at all conditions, except at a 5% (dry wt.) solids concentration. Carbonization of food waste and associated packaging materials also results in net positive balances, but energy needs for solids post-processing are significant. Advantages associated with carbonization are not fully realized when only evaluating process energetics. A more detailed life cycle assessment is needed for a more complete comparison of processes.     

优选粉煤灰制备人工合成沸石及去除氨氮研究

7种粉煤灰样品的物理化学性质,如元素组成、结晶相组成、比表面积、灼失量、阳离子交换容量和pH得到表征。采用熔融法提取硅铝效率作为粉煤灰原料优选的依据,并通过L9（34）正交实验研究氢氧化钠投加量、熔融温度、氢氧化钠提取液浓度和体积对于硅铝提取效果的影响。结果表明,湿式除尘技术收集的低品位粉煤灰比电除尘技术所收集粉煤灰更...     

Potential utilization of riverbed sediments by hydrothermal solidification and its hardening mechanism

Hydrothermal solidification of riverbed sediments (silt) has been carried out in a Teflon (PTFE) lined stainless steel hydrothermal apparatus, under saturated steam pressure at 343–473 K for 2–24 h by calcium hydrate introduction. Tobermorite was shown to be the most important strength-producing constituent of the solidified silt. A longer curing time or a higher curing temperature was shown to be favorable to the tobermorite formation, thus promoting strength development; however, overlong curing time (24 h) seemed to affect the strength development negatively. The hardening mechanism consisted of the crystal growth/morphology evolution during the hydrothermal process. The species dissolved from the silt were precipitated first as fine particles, and then some of the particles seemed to build up the rudimental morphology of calcium silicate hydrate (CSH) gel. The CSH gel, with precipitated particles, appeared to cause some reorganization within the matrix, which made the matrix denser and thus gave an initial strength development. Tobermorite, transformed inevitably from the CSH gel, reinforced the matrix with its interlocked structure, and thus further promoted the strength development.