Adsorption performance of suitable nanostructured novel composite adsorbent of poly(N-methylaniline) for removal of heavy metal from aqueous solutions

Poly(N-methylaniline) (PNMA) composite composed of N-methylaniline and poly(ethanol) was prepared by in situ polymerization technique and characterized using FTIR, SEM-EDS and XRD instruments. Characterization of product revealed that this composite is crystalline in nature and the particles size is less than100 nm. The potential of this composite in removal of Cr(VI) ions from synthetic aqueous effluents was investigated by batch sorption system. The experimental results confirmed that this adsorbent has the potential application for removal of Cr(VI) ions from aqueous solution with the sorption capacity of 125 mg/g of Cr(VI)/0.1 g of adsorbent.     

EXPERIMENTAL INVESTIGATION ON ADSORPTION OF AMIDO BLACK 10B DYE ONTO ZEOLITE SYNTHESIZED FROM FLY ASH

This work presents experimental studies on adsorptive removal of Amido black 10B dye using a low-cost zeolite synthesized from fly ash to study the effect of various parameters, namely pH, temperature, agitation speed, adsorption time, zeolite loading, and dye concentration, on dye removal efficiency. Dye removal efficiency increased with increase in adsorbent dosage, adsorption time, and stirrer speed, and the optimal values of zeolite dose, adsorption time, and stirrer speed were found to be 10 g/L, 6 h, and 300 rpm respectively. On the other hand, dye removal efficiency decreased with increase in the initial dye concentration as well as temperature, indicating that the adsorption process is exothermic and is effective at low concentrations of adsorbate. Maximum dye removal was obtained at low pH values (between 2 and 5), indicating the fact that the zeolite surface is positively charged. Experimental data matched well with the pseudo-first-order kinetic model and the Freundlich equilibrium isotherm. The most important observation in this work is that zeolite synthesized from fly ash could act as a very effective adsorbent for the removal of amido black dye from its aqueous solutions.     

Prediction of gaseous pollutants and heavy metals during fluidized bed incineration of dye sludge

This research provides an equilibrium model for predicting both the emission of gaseous pollutants and the fate of heavy metals during incineration of biologically treated dye sludge in a bench-scale fluidized bed incinerator. Major gaseous pollutants and hazardous trace heavy metals have been also measured under various operating conditions. The predicted values, which were derived by using a thermodynamic equilibrium model, can be used to determine the optimum operating parameters and the risk associated with hazardous waste incineration by means of verifying experimental data. However, prediction of NO_x emission using a thermodynamic equilibrium model during incineration of waste was not simple. The reason is that the variation of NO_x emission during incineration of waste was affected by the various operating parameters, such as air-fuel ratio(λ _T ), primary air factor(λ ₁ /λ _T ), combustor geometry, method of heat release, and preheating of combustion air. According to the distributions of Cr and Pb simulated by the equilibrium model, all of the Cr in the feed was retained in the ash as the solid phase of Cr₂CO₃. However, most Pb was retained in the ash during incineration as the solid phase of PbSO₄, or heterogeneously deposited onto the fly ash as PbO(g) when the combustion gas becomes cool. Presented at the Int’/Sym. on Chem. Eng. (Cheju, Feb. 8–10, 2001), dedicated to Prof. H. S. Chun on the occasion of his retirement from Korea University.     

勃聚糖为基质的染料亲和吸附剂对重金属离子的吸附平衡及动力学研究

以反相悬浮交联法制备了壳聚糖微球载体，并偶联染料配体（Cibacron Blue F3GA），制得了新型染料亲和吸附剂。研究了吸附剂与金属离子Cu^2＋、Pb^2＋、Cd^2＋之间的吸附行为。结果表明，在较高的初始金属离子浓度（200-500mg·L^-1）下，金属离子在吸附剂中的平衡吸附过程较好地符合Lanfmiur吸附等温试，吸附剂对 Cu^2＋、Pb^2＋、Cd^2＋的最大吸附量分别为92.12、115.40、39.78mg·g^-1；吸附动力学可用拟二极速认方程来措述，计算值与实测值物合甚好；吸附剂对各重金属离子的吸附选择性依次为Pb^2＋〉Cu^2＋〉Cd^2＋     

一种金属有机配位聚合物对甲基紫的吸附动力学研究

室温下合成一种金属有机配位聚合物Zn-MOFs,研究Zn-MOFs对染料甲基紫的吸附作用,通过探究不同吸附时间对Zn-MOFs吸附性能的影响判断其吸附的动力学及等温吸附模式。结果表明:Zn-MOFs对亚甲基蓝及甲基紫的吸附过程均更好地符合Langmuir等温吸附模型,其吸附动力学过程均可用二级动力学方程描述。     

壳聚糖为基质的染料亲和吸附剂对重金属离子的吸附平衡及动力学研究

以反相悬浮交联法制备了壳聚糖微球载体,并偶联染料配体(CibacronBlueF3GA),制得了新型染料亲和吸附剂。研究了吸附剂与金属离子Cu2 、Pb2 、Cd2 之间的吸附行为。结果表明,在较高的初始金属离子浓度(200￣500mg·L-1)下,金属离子在吸附剂中的平衡吸附过程较好地符合Langmiur吸附等温式,吸附剂对Cu2 、Pb2 、Cd2 的最大吸附量分别为92.12、115.40、39.78mg·g-1;吸附动力学可用拟二级速率方程来描述,计算值与实测值吻合甚好;吸附剂对各重金属离子的吸附选择性依次为:Pb2 >Cu2 >Cd2 。     

1250°C liquidus for the CaO–MgO–SiO2–Al2O3–TiO2 system in air

Ti-bearing blast furnace slags have been regarded as an important secondary material in modern society, and the efficient recycling of Ti oxides from it is of key interest. For this reason, more thermodynamic data is needed regarding the phase relations in different composition ranges and sections. Therefore, the equilibrium phase relations of CaO–MgO–SiO₂–Al₂O₃–TiO₂ system in a low w(CaO)/w(SiO₂) ratio of 0.6–0.8 at 1250 °C in air and fixed concentrations of MgO and Al₂O₃, were investigated experimentally using a high temperature equilibration and quenching method followed by SEM-EDS (Scanning Electron Microscope and Energy Dispersive X-ray Spectrometer) analyses. The equilibrium solid phases of perovskite (CaO·TiO₂), a pseudo-brookite solid solution (MgO·2TiO₂, Al₂O₃·TiO₂)_ss, and anorthite (CaO·Al₂O₃·2SiO₂) were found to coexist with the liquid phase at 1250 °C. The calculated results of Factsage and MTDATA were used for comparisons, and significant discrepancies were found between predictions and the experimental results. The 1250 °C isotherm has been constructed and projected on the CaO–SiO₂–TiO₂-8 wt.% MgO-14 wt% Al₂O₃ quasi-ternary plane of the phase diagram. The obtained results provide new fundamental data for Ti-bearing slag recycling processes, and they add new experimental features for thermodynamic modeling of the high-order titanium oxide-containing systems.     

丁烯氧化脱氢制丁二烯体系的热力学计算与分析

计算了正丁烯氧化脱氢制丁二烯体系中各反应的标准摩尔反应焓、标准摩尔吉布斯自由能、平衡常数,并利用Gibbs自由能最小法计算了反应体系的热力学平衡组成。结果表明,正丁烯的氧化脱氢与完全氧化反应在热力学上均可完全进行,但是丁二烯的产率受热力学平衡限制。因此,提高丁二烯产率的关键在于开发高性能的催化剂,从动力学上角度充分抑制COx的生成反应。     

Improving the performance of an active carbon-nitrogen adsorption cryocooler by thermal regeneration

Thermodynamic analysis was done on single and two stage active carbon nitrogen adsorption cryocoolers to study the effect of thermal regeneration on the performance. Heat regeneration within compressors operating in the same temperature range is considered. From the analysis done on 80 K cooler and 117.5 K cooler, it is found that dramatic efficiency improvement is possible with the use of compressor heat regeneration techniques.     

Adsorption equilibria of reactive dye onto highly polyaminated porous chitosan beads

The adsorption of vinyl sulfone type reactive black 5 (RB 5) in aqueous solution onto chitosan beads and cross-linked chitosan beads with glutaraldehyde has been investigated in terms of initial pH and temperature of the solution. The adsorption equilibrium data were correlated with three adsorption models, such as Langmuir, Freundlich and Sips isotherms. Among them, the Freundlich isotherm best fit the data over the entire pH and temperature range of the solution. The adsorption capacity of RB 5 onto chitosan beads and cross-linked chitosan beads increased with decreasing initial pH and with increasing temperature. Equilibrium amount of RB 5 on chitosan beads was greater than that of cross-linked chitosan beads at the same initial pH values. Thermodynamic studies have also been carried out and values of standard free energy (°Gℴ), enthalpy (°Hℴ) and entropy (°Sℴ) were calculated.     

Phase equilibria and liquidus surface of CaO-SiO2–5 wt%MgO-Al2O3-TiO2 slag system

The lack of phase equilibria relations and liquidus surface thermodynamic information for CaO-SiO₂–5?wt%MgO-Al₂O₃-TiO₂ system has seriously restricted the comprehensive utilization of the titanium resources. In present study, the phase equilibrium relationships were investigated for CaO-SiO₂–5?wt%MgO-Al₂O₃-TiO₂ phase diagram system at 1300?°C and 1400?°C using the high temperature equilibrium technique followed by X-Ray Fluoroscopy (XRF), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscope (EDX) analysis. In the composition range studied, the liquid phase, melilite solid solution phase and CaO·TiO₂ phase were found. The two-phase equilibrium of liquid coexisting with CaO·TiO₂ phase was intensively dicussed, and the spatial liquidus surfaces at 1300?°C, 1400?°C and 1450?°C (data from literatures only) for liquid coexisting with CaO·TiO₂ phase were first constructed in CaO-SiO₂–5?wt%MgO-Al₂O₃-TiO₂ tetrahedral phase diagram, which can realize a visual understanding of the phase relation change trendency in 3-dimensional space.     

Studies on auramine dye adsorption on psidium guava leaves

Removal of auramine dye from aqueous waste solutions was investigated by using very cheap and biosorbent, withered guava tree leaves and activated carbon. Guava leaves are readily available in the western and northern parts of India throughout the year, and hence form a cost effective alternative for removal of dyes from waste waters. The optimum contact time was found to be 120 min. in a pH range of 8–9 for 92–94% removal of the dye from aqueous solutions containing 150 mg/L of auramine dye using 2 g of the adsorbent. The effect of pH, dye concentration, sorbent dosage, temperature and contact time on the dye removal efficiency has been studied. Experimental results were found to fit both Freundlich and Langmuir models. Since the dye contains a cationic species, the removal efficiency was highest in a pH range of 8–9. Continuous adsorption studies in a packed column showed 100% removal efficiency for a flow rate of 10 ml·min⁻¹. When compared with the activated carbon, it was also found that adsorbent derived from guava leaves is more efficient in removal of dye.     

吗啡啉-正丁醇体系等压汽液相平衡研究

采用泵式沸点仪测定了吗啡啉-正丁醇二元体系在常压下的汽液平衡数据,并用间接法由TPX推算了与之平衡的汽相组成,用最小二乘法求出了该系统的液相活度系数模型参数,由模型参数推算的泡点与实验值符合良好,所得数据通过了热力学一致性检验。     

Adsorption of thorium(IV) on MX-80 bentonite: Effect of pH, ionic strength and temperature

The adsorption of Th(IV) on MX-80 bentonite as a function of pH, ionic strength, Th(IV) concentration and temperature was studied by using batch technique. The results indicated that the adsorption of Th(IV) on bentonite depended on pH, ionic strength and temperature. The adsorption of Th(IV) decreased with increasing temperature, indicating that the adsorption process of Th(IV) on bentonite was exothermic. The experimental data of Th(IV) adsorption isotherms were obtained at T = 293, 303, 313, and 323K, and were analyzed with the Langmuir and Freundlich models, showing that the Langmuir model fitted the adsorption data better than the Freundlich model. Thermodynamic parameters, such as ΔH^o, ΔS^o, and ΔG^o, were calculated from the slope and intercept of the linear plot of lnK_d against 1000/T.