超高交联树脂对酚类化合物吸附动力学研究

文章重点研究超高交联树脂NDA-100对苯酚的静态吸附动力学,通过动力学实验探讨了不同温度和初始浓度对吸附苯酚的影响,实验结果表明:苯酚在NDA-100树脂上的静态吸附动力学过程符合准二级动力学方程,其吸附速率受膜扩散和颗粒内扩散共同控制,对于高浓度的苯酚溶液微孔填充占主导作用,而低浓度的苯酚溶液表现为先经过大孔吸附后经由微孔填充两个阶段,低浓度吸附时出现双平台动力学现象。进一步阐述了超高交联树脂对于酚类化合物的吸附机理,为树脂固定床吸附酚类化合物的研究和实际工业应用提供理论基础。     

功能纤维处理含铬废水的初步研究

试验研究筛选了各种离子交换纤维对Cr^3 和Cr^6 的静态和动态吸附性能，试验结果表明所制磺酸型和羧酸型功能纤维对Cr^3 的静态吸附量在25mg/g-45mg/g纤维的范围，动态吸附穿透曲线比相应的树脂好，但穿透点之前出口液中Cr^3 浓度偏高，所制五种碱性功能纤维对Cr^6 的交换吸附量比较高，最高达293mg/g，最佳吸附pH值都在1－2，其中PVA－g-4VP-季铵化纤维比日本树脂吸附量高很多，它还具有很好的动态吸附Cr^6 的效果，穿透点前的铬浓度近乎为零穿透点突跃明显。     

矿化垃圾柱吸附能力预测模型

建立数学模型对矿化垃圾柱的吸附能力进行理论预测。通过改变模型参数得到矿化垃圾柱的不同吸附穿透曲线，分析穿透曲线的变化规律，判定参数的优劣，确定垃圾柱吸附运行最优工况。为矿化垃圾柱的设计提供一定的理论依据。     

磁性离子交换树脂对模拟水中四环素的吸附特性研究

采用静态实验研究了溶液中四环素在磁性离子交换树脂上的吸附行为,考察了反应物初始浓度,初始p H值等因素对吸附效果的影响,分析了吸附动力学、吸附等温线模型和吸附热力学,并阐明了吸附机制。结果表明:磁性离子交换树脂对四环素具有良好的吸附效果;准二级动力学模型能更好的描述磁性离子交换树脂对四环素的吸附过程;Freundlich模型更适合描述磁性离子交换树脂对四环素的吸附平衡过程,D-R模型说明吸附过程包含离子交换作用;中性和酸性条件下磁性离子交换树脂对四环素的吸附效果较好;磁性离子交换树脂吸附四环素是自发、吸热和熵增加的反应过程,升温有利于吸附。     

利用炼化RO浓水再生阳离子树脂研究

对几种树脂的吸附容量开展进水浓度梯度实验.考察常见干扰因子对树脂吸附的影响情况·并使用现场水样考察了实际情况下的树脂可重复利用性,筛选出适用于本实验的树脂。使用NaCl对饱和树脂进行再生.寻找浓度和用量对树脂再生效果的影响。最终,使用炼化反渗透(RO)浓水对饱和树脂进行再生,分析得出可以使用炼化RO浓水再生树脂的结论。     

5A分子筛基吸附剂制备及脱除H_2S性能研究

以价格低廉的5A型分子筛为基体,采用浸渍法负载一定量的活性物质制备成化学吸附剂材料,并通过气体穿透实验研究其脱除H_2S气体的性能。结果表明,负载20wt%、200℃下焙烧3h的ZnO/5A分子筛化学吸附剂对H_2S气体具有最佳的吸附性能,穿透时间达50min,穿透吸附量达到3.44mg/g。     

改性介孔二氧化硅对硫化氢的吸附研究

以均匀沉淀法合成金属氧化物改性介孔二氧化硅,并通过气体穿透实验考察了其吸附H_2S气体的性能。实验表明,CuO负载量为40%(质量分数)、450℃下焙烧4h制备的改性二氧化硅具有最佳的吸附性能,其穿透时间为247.3min,穿透吸附量达50.5mg/g。     

XDA-1型大孔吸附树脂对水中氯仿的吸附性能

研究了XDA-1型大孔吸附树脂对用自来水配制的低浓度溶液中氯仿的动态吸附能力,以及浓度、流速、温度和pH等因素对吸附过程的影响.结果显示,采用XDA-1大孔树脂吸附水中的氯仿,其吸附效率可达99%以上,泄漏点前的吸附量为160mg/ml.采用热空气热解吸方式回收氯仿,回收率达85%,为含氯仿工业废水的处理提出一种新的处理工艺.     

酸水汽提净化水中酚的治理技术研究

采用吸附法对酸水汽提净化水中的酚进行了处理。这种方法不仅可以满足对实验浓度酚的处理,同时可以回收酚。通过吸收过程及不同流速对比实验得出:树脂的吸附效果显著,吸附能力较强,吸附时间较长;净化水的流速与吸附效果具有一定的线性关系;不同流速吸附效果不同,对应树脂需要再生的时间也不同。应用结果表明:吸附法中较可行的方法为树脂吸附法。     

炼油污水深度处理回用工艺中阳离子树脂污染物脱除性能研究

实验考察了深度处理后的炼油污水用于锅炉时的性能状况,分析了污水化学需氧量(COD)、硬度对树脂吸附脱氨性能的影响。研究表明,在对炼油污水进行深度处理时,污水的COD、硬度严重影响树脂对氨、氮的吸附。树脂对硬度的吸附率高于对氨、氮的吸附率,稳态时树脂能使COD降低60%。树脂脱氨不适合于对炼油废水深度处理时作为脱氨的主要工艺,应置于深度处理的后段。氨、氮量及COD均被有效地降低后,再对水的硬度进行处理。     

Adsorption of methylene blue from aqueous solution by jackfruit (Artocarpus heteropyllus) leaf powder: A fixed-bed column study

Continuous fixed-bed studies were undertaken to evaluate the efficiency of jackfruit leaf powder (JLP) as an adsorbent for the removal of methylene blue (MB) from aqueous solution under the effect of various process parameters like bed depth (5–10 cm), flow rate (30–50 mL/min) and initial MB concentrations (100–300 mg/L). The pH at point of zero charge (pH_PZC) of the adsorbent was determined by the titration method and a value of 3.9 was obtained. A FTIR of the adsorbent was done before and after the adsorption to find the potential adsorption sites for interaction with methylene blue molecules. The results showed that the total adsorbed quantities and equilibrium uptake decreased with increasing flow rate and increased with increasing initial MB concentration. The longest breakthrough time and maximum MB adsorption were obtained at pH 10. The results showed that the column performed well at low flow rate. Also, breakthrough time and exhaustion time increased with increasing bed depth. The bed-depth service time (BDST) model and the Thomas model were applied to the adsorption of MB at different bed depths, flow rates, influent concentrations and pH to predict the breakthrough curves and to determine the characteristic parameters of the column that are useful for process design. The two model predictions were in very good agreement with the experimental results at all the process parameters studied indicating that they were very suitable for JLP column design.     

Biosorption of Reactive Black 5 from aqueous solutions by chitosan: Column studies

Fixed-bed column studies were carried out to investigate the dynamic sorption of Reactive Black 5 (RB5) onto chitosan. The effect of operating parameters such as initial dye concentration, superficial flow velocity, bed height and particle size on the sorption of RB5 onto chitosan was studied. Column regeneration, dye recovery and the possibility of reusing the regenerated chitosan were also investigated. The results show that both the breakthrough curves and the adsorption parameters of the column were strongly affected by the operating parameters studied. An analysis of the breakthrough curves indicated that adsorption was affected by mass transfer limitations, probably due to intraparticle diffusion. An empirical model was applied to describe the breakthrough curves, while the Bohart–Adams and BDST models were used to determine the operating parameters useful in the process design. Elution of the column with 0.01 mol L^?1 NaOH allowed the chitosan to be regenerated and the dye to be recovered and concentrated. The concentration factor was 10. Several cycles of adsorption–elution showed that the regenerated chitosan retained good adsorption efficiency and the elution efficiency was always higher than 80%.     

Application of surface molecular imprinting adsorbent in expanded bed for the adsorption of Ni(2+) and adsorption model

A new surface molecular imprinting adsorbent (SMIA) was used in an expanded bed. The expansion ratio and adsorption performance were studied at different volumetric rates, inlet concentrations, and pH values. A model based on the Adams-Bohart adsorption model of breakthrough curves was established. The predicted curves had good agreement with the experimental curves. The breakthrough time (T(1/2)) decreased with increasing inlet concentration when the outlet concentration was half the initial concentration (C/C(0)=0.5). The inlet concentration had little effect on the adsorption rate constant (k(1)) value when the initial concentration (C(0)) was above 150 mg/L. However, T(1/2) values increased with increasing initial pH of the inlet solution, and the k(1) value decreased due to the competition between H(+) and Ni(2+).     

Removal of Pb(II) ions from aqueous solution using activated tea waste: Adsorption on a fixed-bed column

An inexpensive and effective adsorbent was developed from waste tea leaves for the dynamic uptake of Pb(II). Characterization of the adsorbents showed a clear change between physico-chemical properties of activated tea waste and simply tea waste. The purpose of this work was to evaluate the potential of activated tea waste in continuous flow removal of Pb(II) ions from synthetic aqueous effluents. The performance of the system was evaluated to assess the effect of various process variables, viz., of bed height, hydraulic loading rate and initial feed concentration on breakthrough time and adsorption capacity. The shape of the breakthrough curves was determined for the adsorption of Pb(II) by varying different operating parameters like hydraulic loading rate (2.3–9.17 m³/h m²), bed height (0.3–0.5 m) and feed concentration (2–10 mg/l). An attempt has also been made to model the data generated from column studies using the empirical relationship based on the Bohart–Adams model. There was an acceptable degree of agreement between the data for breakthrough time calculated from the Bohart–Adams model and the present experimental study with average absolute deviation of less than 5.0%. The activated tea waste in this study showed very good promise as compared with the other adsorbents available in the literature. The adsorbent could be suitable for repeated use (for more than four cycles) without noticeable loss of capacity.     

Green coconut shells applied as adsorbent for removal of toxic metal ions using fixed-bed column technology

This study applies green coconut shells as adsorbent for the removal of toxic metal ions from aqueous effluents using column adsorption. The results show that a flow rate of 2 mL/min and a bed height of 10 cm are most feasible. Furthermore, larger amounts of effluent can be treated for removal of single ions. The breakthrough curves for multiple elements gave the order of adsorption capacity: Cu⁺² > Pb⁺² > Cd⁺² > Zn⁺² > Ni⁺². Real samples arising from the electroplating industry can be efficiently handled.     

Adsorption characteristics of Cu and Ni on Irish peat moss

Peat has been widely used as a low cost adsorbent to remove a variety of materials including organic compounds and heavy metals from water. Various functional groups in lignin allow such compounds to bind on active sites of peat. The adsorption of Cu(2+) and Ni(2+) from aqueous solutions on Irish peat moss was studied both as a pure ion and from their binary mixtures under both equilibrium and dynamic conditions in the concentration range of 5-100mg/L. The pH of the solutions containing either Cu(2+) or Ni(2+) was varied over a range of 2-8. The adsorption of Cu(2+) and Ni(+2) on peat was found to be pH dependent. The adsorption data could be fitted to a two-site Langmuir adsorption isotherm and the maximum adsorption capacity of peat was determined to be 17.6 mg/g for Cu(2+) and 14.5mg/g for Ni(2+) at 298 K when the initial concentration for both Cu(2+) and Ni(2+) was 100mg/L, and the pH of the solution was 4.0 and 4.5, respectively. Column studies were conducted to generate breakthrough data for both pure component and binary mixtures of copper and nickel. Desorption experiments showed that 2mM EDTA solution could be used to remove all of the adsorbed copper and nickel from the bed.     

A two stage batch adsorber design for methylene blue removal to minimize contact time

The adsorption of methylene blue onto bentonite in a batch adsorber has been studied. Three kinetic models, the intraparticle diffusion equation and the pseudo first and second order equations, were selected to follow the adsorption process. Kinetic parameters, rate constants, equilibrium adsorption capacities and related correlation coefficients for each kinetic model were calculated and discussed. It was shown that the adsorption of methylene blue onto bentonite could be described by the pseudo second order equation. Adsorption of methylene blue onto bentonite followed the Langmuir isotherm. A model has been developed for the design of a two stage batch adsorber based on pseudo second order adsorption kinetics. The model has been optimized with respect to operating time in order to minimize total contact time to achieve a specified amount of methylene blue removal using a fixed mass of adsorbent. The results of two stage batch adsorber design studies showed that the required times for specified amounts of methylene blue removal significantly decreased. This design is particularly suitable for low-cost adsorbents/adsorption systems when minimising contact time is a major operational and design criterion and a significant volume of effluent needs to be treated in the minimum amount of time.