Thermodynamic and kinetic study of phenol degradation by a non-catalytic wet air oxidation process

This work is dedicated to an accurate evaluation of thermodynamic and kinetics aspects of phenol degradation using wet air oxidation process. Phenol is a well known polluting molecule and therefore it is important having data of its behaviour during this process. A view cell is used for the experimental study, with an internal volume of 150 mL, able to reach pressures up to 30 MPa and temperatures up to 350 °C. Concerning the thermodynamic phase equilibria, experimental and modelling results are obtained for different binary systems (water/nitrogen, water/air) and ternary system (water/nitrogen/phenol). The best model is the Predictive Soave Redlich Kwong one. This information is necessary to predict the composition of the gas phase during the process. It is also important for an implementation in a process simulation. The second part is dedicated to kinetics evaluation of the degradation of phenol. Different compounds have been detected using GC coupled with a MS. A kinetic scheme is deduced, taking into account the evolution of phenol, hydroquinones, catechol, resorcinol and acetic acid. The kinetic parameters are calculated for this scheme. These data are important to evaluate the evolution of the concentration of the different polluting molecules during the process. A simplified kinetic scheme, which can be easily implemented in a process simulation, is also determined for the direct degradation of phenol into H₂O and CO₂. The Arrhenius law data obtained for the phenol disappearance are the following: k = 1.8 × 10⁶ ± 3.9 × 10⁵ M⁻¹ s⁻¹ (pre-exponential factor) and E_a = 77 ± 8 kJ mol⁻¹ (activation energy).     

Efficient removal and mechanisms of water soluble aromatic contaminants by a reduced-charge bentonite modified with benzyltrimethylammonium cation

A novel strategy utilizing the phenyls interaction and the hydrophobic affinity of available siloxane surface in the interlayer of bentonite was proposed to improve the sorption capabilities of organobentonites for water soluble aromatic contaminants. A unique organobentonite (65BTMA) was synthesized by intercalating benzyltrimethylammonium cation (BTMA⁺) into the interlayer of a reduced-charge bentonite with cation exchange capacity (CEC) of 65 cmol kg⁻¹. Phenol, aniline and toluene were used as model compounds of water soluble aromatic contaminants. Their respective removal efficiencies by 65BTMA were achieved at 83.3%, 89.2% and 97.3% at the initial concentration of 20 mg l⁻¹. To reveal the sorption mechanism, sorption characteristics of aromatic contaminants to 65BTMA were compared with that of aliphatic contaminants in similar molecular size. And various organobentonites were prepared by combining TMA⁺ (tetramethylammonium), BTMA⁺, HTMA⁺ (heptyltrimethylammonium) and CTMA⁺ (cetyltrimethylammonium) with two bentonites (CEC = 108 and 65 cmol kg⁻¹). To 65BTMA, sorption magnitudes of aromatic contaminants were much greater than that of aliphatic compounds with similar size; and dramatically higher than those to other organobentonites at low pollutant concentrations. These observations revealed that the strong phenyls interactions contributed significantly to sorb the aqueous soluble aromatic contaminants to 65BTMA (>90%), and which favored to design uniquely powerful sorbents.     

非有机溶剂高聚物萃取分离测定水样中苯酚的研究

在酸性溶液中,利用聚乙二醇-4000对水样中的苯酚进行萃取．并在聚乙二醇-4000、氨-氯化铵缓冲体系里对萃取相中的苯酚定量测定。在实验条件下,水样中苯酚被聚乙二醇-4000定量萃取并被4氨基安替比林定量测定。该方法快速、简单、无毒、为水样中苯酚的分离测定提供了一种较好的方法。     

生活污水中糖类测试方法研究

分别用蒽酮比色、苯酚-硫酸及气相色谱法3种测试方法测试了上海市某生活小区生活污水的糖类组成.试验结果表明,蒽酮比色法测试糖类浓度的准确性与精确性优于苯酚-硫酸法,但不能得出污水中糖类的详细组成情况;与蒽酮比色法和苯酚-硫酸法相比,气相色谱法不仅能得出污水中糖类的详细组成,而且还具有较高的精密度.气相色谱法测得的生活污水中各种单糖,如木糖、甘露糖、葡萄糖、半乳糖、鼠李糖、核糖、岩藻糖的质量浓度分别为8.25、 6.02、5.52、4.80、4.44、4.41、2.66 mg/L.     

Use of advance oxidation process to improve the biodegradability of olive oil mill effluents

In this study, recalcitrant total phenol (TPh) and organic matter removal were investigated at olive mill wastewater (OMW) in sequential Coagulation and Fenton system. This study focused on different operational parameters such as pH, H₂O₂, and Fe²⁺ dosages, and [Fe²⁺]/[H₂O₂] ratios. The optimum conditions were determined as; pH = 3; [Fe²⁺] = 2.5 g/L; [Fe²⁺]/[H₂O₂] = 2.5. A higher treatment efficiency was achieved at sequential Coagulation and Fenton system (COD, 65.5%) and TPh, 87.2%), compared to coagulation process (COD, 51.4%; total organic carbon (TOC), 38.6% and total nitrogen (TN) 52.1%). This study demonstrated that the Coagulation and Fenton process has a potential for efficient removal of phenolic pollutants from wastewater.     

苯酚降解菌Y_1的分离与鉴定

旨在从微生物降解的角度出发,解决苯酚大量应用带来的含酚废水对环境污染问题.采用富集培养、驯化筛选和平板划线等方法,从某化工厂废水中分离得到4株苯酚降解菌.利用4-氨基吡啉分光光度法测定其苯酚降解能力,筛选出降解率较高的菌株Y_1.经形态学观察、生理生化鉴定和16S rDNA序列分析,将该菌初步鉴定为苏云金芽孢杆菌(Ba...     

Microbiological analysis of multi-level borehole samples from a contaminated groundwater system

A range of bacteriological, geochemical process-related and molecular techniques have been used to assess the microbial biodegradative potential in groundwater contaminated with phenol and other tar acids. The contaminant plume has travelled 500 m from the pollutant source over several decades. Samples were obtained from the plume using a multi-level sampler (MLS) positioned in two boreholes (boreholes 59 and 60) which vertically transected two areas of the plume. Activity of the microbial community, as represented by phenol degradation potential and ability to utilise a range of substrates, was found to be influenced by the plume. Phenol degradation potential appeared to be influenced more by the concentration of the contaminants than the total bacterial cell numbers. However, in the areas of highest phenol concentration, the depression of cell numbers clearly had an effect. The types of bacteria present were assessed by culture and DNA amplification by polymerase chain reaction (PCR). Bacterial groups or processes associated with major geochemical processes, such as methanogenesis, sulphate reduction and denitrification, that have the potential to drive contaminant degradation, were detected at various borehole levels. A comparative molecular analysis of the microbial community between samples obtained from the MLS revealed the microbial community was diverse. The examination of microbial activity complemented those results obtained through chemical analysis, and when combined with hydrological data, showed that MLS samples provided a realistic profile of plume effects and could be related to the potential for natural attenuation of the site.     

酚二磺酸法测定硝酸盐氮有关问题的探讨

酚二磺酸光度法测定硝酸盐氮是《水和废水监测分析方法》(第三版)中的推荐方法,由于它的测定范围较宽,显色稳定而被采用;但是此方法的反应条件要求严格,较难控制,造成加标回收率不稳定。经过多年的试验摸索,发现对试验产生影响的因素有显色剂、硝化条件、干扰、取样量等。     

微型快速穿透实验技术在活性炭液相吸附中的应用

穿透实验为液相吸附应用中预测实际活性炭床运行的必要测试.微型快速穿透(MCRB)实验技术采用粉碎筛分后的微小颗粒活性炭和微型穿透柱,可以加快实验速度、节省时间和资源,同时避免传统穿透实验中常遇到的问题.该实验技术操作较简单、用途广泛和设备要求较低,适合在国内大多数实验室中进行.MCRB实验技术弥补中国微型穿透实验的空白,与中小型、小型穿透柱实验方法构成完整活性炭穿透实验方法体系.     

膨润土吸附剂对水中酚吸附性能研究

讨了用羟基铝、硫酸处理过的膨润土对水中酚的吸附性能．试验结果表明：酚径膨润土吸附剂吸附后，其去除率为７３．８８％，处理水再经活性炭吸附，酚去除率可达９９．８％、降至０．５ｍｇ／Ｌ以下．