Water Purification from Heavy Metal Ions in a Packed Column

The process of adsorption from water solutions containing ternary system of Cu(II), Zn(II) and Ni(II) ions in time-variable conditions in a packed column with lyophilized chitosan beads is considered. The system of partial differential equations describing the adsorption column, due to the assumption of a properly defined variable is transformed into a system of ordinary nonlinear equations which enables the identification of object parameters in simple experiments. Analytical solution of that system was possible due to the assumptions made regarding the equation describing sorption kinetics. Using experimental data, the effective diffusion coefficient D_eff and the sorption kinetic constants K in the real environment were identified. The sorption capacity q* was obtained in separate sorption equilibrium experiments. Using a mathematical model the influence of initial concentration and solution flow rate on the breakthrough curve was determined. The approach which is presented provides a new method for modeling of sorption in a packed column.     

Cleaning Water Contaminated with Heavy Metal Ions Using Pyrolyzed Biochar Adsorbents

The extraction of pollutants from water using activated biochar materials is a low cost, sustainable approach for providing safe water in developing countries. The adsorption of copper ions, Cu(II), onto pyrolyzed and activated dried banana peel was studied and compared with the adsorption of copper ions onto a commercial activated carbon, F-400. Both the physical and chemical properties of the banana peel and activated carbon were measured. Pyrolysis of dried banana peels resulted in the formation of a large, porous surface area adsorbent with strongly negative surface charges.

Screening studies, which were designed to evaluate the effect of the mass of the adsorbent, pH of the solution, tumbling time, and initial Cu(II) concentration were conducted for each adsorbent. Equilibrium adsorption data were also analyzed, and the Freundlich isotherm resulted in a better fit than the Langmuir isotherm. The degree of favorability of adsorption of Cu(II) ions and adsorption capacity were 1.25 and 351.1 mg/g for pyrolyzed banana peel, respectively. The sorption kinetics fit a pseudo-second order equation. The mechanism of adsorption of metal ions on pyrolyzed banana peel followed ion exchange and electrostatic interactions resulting in the complexation of adsorbed ions.     

Comparison of Experimental and Simulated Adsorption of Binary Metal Ions using Sawdust Modified by Citric Acid

With the aim of removing binary metal ions from aqueous solutions, the adsorption characteristics of sawdust modified with citric acid are investigated using adsorption kinetics and isotherms in both an experiment and a numerical simulation. The adsorption of metal ions is characterized by the competitive adsorption in binary metal ion systems that results from the stability constants between metal ions and citrate in the modified sawdust. These findings suggest that competitive adsorption and the affinities of the metal ion adsorbents play important roles in the removal of metal ions and that the numerical simulation can predict the adsorption characteristics of the modified sawdust.     

四钛酸钾晶须吸附废水中重金属离子的研究

以四钛酸钾晶须(PTW)作为去除工业废水中重金属离子铅、镉的吸附剂,考察了吸附剂的用量、吸附时间和酸度对吸附效果的影响.研究结果表明:吸附效率随着吸附剂用量的增加、吸附时间的延长以及pH值的升高而提高,但吸附容量却随着吸附剂用量的增加而降低.水中铅、镉离子在PTW上的吸附可用Freundlich方程进行描述.     

纤维素的改性及对重金属离子去除的研究进展

本文在对纤维素的性质、结构和来源进行介绍的基础上,重点阐述了近年来国内外对纤维素改性的方法,其中包括醚化反应、酯化反应、接枝共聚反应和模板合成等.同时进一步总结了纤维素基吸附材料在含重金属离子废水中应用的研究进展.     

Synthesis of Amine-Functionalized MCM-41 and MCM-48 for Removal of Heavy Metal Ions from Aqueous Solutions

In this research amino functional mesoporous MCM-41 and MCM-48 materials were prepared in an attempt to develop efficient adsorbents for removal of heavy metals from aqueous solutions. The adsorbents were characterized by XRD, FTIR, and TG-DTG techniques. The synthesized adsorbents were used for the removal of Cu(II), Co(II), Cd(II), and Pb(II) from aqueous solutions for the first time, and the influence of some effective parameters including concentration, initial pH, contact time, and temperature on the sorption process was studied and optimized. Significant adsorption capacities were obtained at low concentrations. The kinetic studies showed that the adsorption process was fast and more than 90% of equilibrium capacity was achieved within 60 min. Experimental kinetic data was well fitted with the pseudo-second-order kinetic model. Thermodynamic parameters computed from the experimental data showed that the adsorption was endothermic and spontaneous.     

化学改性沸石对重金属离子去除的研究进展

随着工业的不断发展,重金属污染程度日益加深,严重危害人类的健康.近年来,化学改性沸石因具有较大的比表面积和较强的离子交换能力,在重金属离子处理领域被广泛应用.然而,在化学改性过程中,由于使用酸、碱、无机盐、有机试剂等改性剂,在能耗、成本以及可持续发展方面仍存在一定弊端.因此,开展沸石化学改性方法的研究,使其简单化、工业...     

粉煤灰合成沸石对混合重金属离子的吸附研究

利用粉煤灰合成沸石吸附混合重金属离子Cu^2＋、Ni^2＋、Pb^2＋、Zn^2＋,考察初始浓度对沸石吸附4种混合重金属离子的吸附效果影响。结果表明：初始浓度对沸石吸附重金属离子的效果影响显著,当混合重金属离子初始浓度不同时,沸石对其去除率也不同。当初始浓度为50mg／L与100mg／L时,重金属离子去除顺序为Cu〉Pb〉Ni〉Zn。当初始浓度提高为200mg／L与300mg／L时,去除顺序变为Cu≈Pb〉Zn〉Ni。沸石对Pb^2＋与Cu^2＋两种重金属离子的吸附性能较强,而对Zn^2＋与Ni^2＋两种重金属离子的吸附能力较弱。     

Amidoximation of Cyano Group for Chelating Ion Exchange of Some Heavy Metal Ions from Wastewater

Ion exchange behavior of some heavy metal ions, Pb²⁺, Ni²⁺, and Cd²⁺, onto amidoximated polyacrylonitrile based Ce(IV) phosphate was investigated. Polyacrylonitrile based Ce(IV) phosphate was prepared and followed by functionalization of the cyano group to amidoxime group with hydroxylamine. The amidoximated resin was characterized using FT-IR and SEM. Removal of Pb²⁺, Ni²⁺, and Cd²⁺ ions from aqueous solution was examined by studying some factors using the batch technique such as effect of pH, contact time, initial metal ion concentration, and temperature. Some kinetic and isotherm models had been applied. The calculated amount of the sorbed values in case of the pseudo-second-order model are closer to the experimental data than that of the pseudo-first-order model, and with a correlation coefficients R² > 0.99. Therefore, the sorption of the three metal ions can be approximated more favorably by the pseudo-second-order model. The sorption process obeys the Freundlich isotherm model. The sorption has an endothermic nature which is indicated by the positive value of the enthalpy change, ΔH, the high positive values of the entropy change, and ΔS show the increased randomness at the solid/solution interface. The obtained negative values of free energy change, ΔG, indicate the feasibility and the spontaneous nature of the sorption process.     

腐殖酸树脂处理含Zn^2＋、Ni^2＋废水的研究

利用泥炭为原料制备出腐殖酸树脂,在动态条件下,研究了腐殖酸树脂对重金属离子Zn^2＋、Ni^2＋的吸附效果及吸附条件。结果表明,在20℃,流速为4mL／min,pH值为5．0～7．0,含Zn^2＋、Ni^2＋浓度分别为70mg／L的废水经过腐殖酸树脂处理,Zn“、Ni。’去除率可达98％以上,且处理后的废水pH值近中性。含Zn^2＋、Ni^2＋浓度分别为32．5mg／L和29．4mg／L,pH值为5．9的电镀废水经腐殖酸树脂处理后,废水中Zn^2＋、Ni^2＋含量明显低于国家排放标准。     

纳米金属氧化物去除水体重金属的研究进展

简要介绍了用于吸附水体重金属的几种纳米金属氧化物,包括:纳米铁氧化物、纳米锰氧化物、纳米铝氧化物、纳米钛氧化物、纳米锌氧化物、纳米镁氧化物、纳米铈氧化物以及纳米金属氧化物复合材料,讨论了各种纳米金属氧化物处理水体重金属的优缺点,并展望了其应用前景。     

膜分离技术在重金属废水处理中的应用

综述了电渗析、液膜、纳滤、超低压反渗透、胶束增强超滤和水溶性聚合物络合超滤等膜技术在废水处理中的研究和应用概况，分析了膜技术在处理重金属废水中存在的主要问题，并对膜技术处理重金属废水的发展前景作了展望。     

NMMO法纤维素膜沉浸过程的传质动力学研究

以Reuvers模型为基础,建立了纤维素/NMMO/水三元体系沉浸过程的传质动力学模型,并利用该模型深入研究了不同工艺条件下膜的成形机理。     

Removal of Heavy Metal Ions from Water by Cross-Linked Potato Di-Starch Phosphate Polymer

Potato di-starch phosphate polymer was synthesized by cross-linking potato starch with phosphorus oxy-chloride in basic medium and was then dispersed (0.2-1%) in aqueous solutions of divalent heavy metal ions (Cu²⁺, Ni²⁺, Zn²⁺, and Pb²⁺), to investigate their removal efficiency by the starch and was found to increase with increase in the polymeric starch content and increase in the heavy metal ion concentration. The removal order was found to be Pb²⁺ (78.1%) > Cu²⁺ (58.5%) > Zn²⁺ (20.5%) > Ni²⁺ (17.3%) against the constant polymeric starch content. UV-Visible, Fluorescence, FT-IR, SEM, and CHN techniques were used for characterization of different complexes formed.     

Removal of Lead (II) Ions from Aqueous Solution Using Eggplant Peels Activated Charcoal

The eggplant peel activated charcoal (EPPAC) was investigated as an adsorbent for the removal of lead II ions from aqueous solution. Three methods were tested for the production of eggplant peel activated charcoal (EPPAC) from eggplant peel charcoal (EPPC), yielding three different products; EPPAC-1, EPPAC-2, and EPPAC-3. The difference among the three methods lies in the primary physical mixing of the EPPC with the activating agent (potassium hydroxide) before heating the mixture in a furnace for activation. The removal efficiency of lead II ions by the three adsorbents was 57.7%, 70.0%, and 60.0% for EPPAC-1, EPPAC-2, and EPPPAC-3, respectively. The optimized activation parameters for EPPAC-2 were: activation time 2 hours, activation temperature 700°C, and activation ratio 1:2 (EPPAC: KOH). Scanning electron microscopy (SEM) revealed that EPPAC-2 has the most porous structure. The surface area of EPPAC-2 was measured to be 739 m²/g. Adsorption kinetics of lead (II) is best described by the pseudo-second-order kinetic model with second order rate constant of 1.70 × 10^?3 g/mg.h at room temperature. The adsorption of lead on EPPAC-2 is found to follow the Langmuir isotherm with a maximum adsorption capacity of 1.4 × 10² mg/g.     

Insights into the Adsorption of Heavy Metals from Wastewater using Diatomaceous Earth

The release of large quantities of heavy metals (e.g., Zn, Cu, Pb, Ni, Cd, etc.) into the natural environment has resulted in a significant number of environmental problems, disorderliness in human physiology, and other biological systems due to their high toxicity to plant, animal, and human life. This review paper explores the feasibility of diatomaceous earth for the adsorption of heavy metals from wastewater, its application in metal adsorption, and wastewater purification. Impregnating the diatomite surface with 0.38 g/g of manganese oxide gave a 2.4-fold increase in the adsorbent surface area. A number of equilibrium studies demonstrated that treated diatomite has a higher removal capacity for heavy metals from water than untreated diatomite. The future challenges and prospect of diatomite were also addressed. Conclusively, it was established that the use of diatomaceous earth is a promising technology in the removal of heavy metals from wastewaters and environment     

Removal of Mercury(II) Ions from Aqueous Solutions using Chemically Modified Banana Stem: Kinetic and Equilibrium Modeling

In this study, removal of mercury(II) ions from aqueous solutions under different experimental conditions using formaldehyde polymerized banana stem (FPBS) has been investigated. Formaldehyde treatment favored the stabilization of the organic substances of banana stem (BS). The adsorbent was characterized using IR, SEM, TG, and potentiometric titration methods. The adsorption efficiency of FPBS was compared with BS and the result showed that FPBS was found to be 1.8 times more effective than BS for mercury(II) removal. The maximum removal of 99.3 and 99.1%, respectively, for 10 and 25 mg/L in 50 mL initial concentrations was obtained at pH 7.0. Kinetic studies revealed that the adsorption occurred in two stages: external mass transport in the first stage and intra-particular diffusion in the second stage. Adsorption was found to be rapid and equilibrium was attained in 60 min. The adsorption equilibrium data fitted the Freundlich isotherm equation reasonably well. The maximum adsorption capacity of FPBS for mercury(II) was found to be 132.25 mg/g. Desorption experiments showed that the process of adsorption was reversible and the adsorbent was easily regenerated with 0.1 M HCl up to 96.0% recovery.     

Review on the Use of Heavy Metal Deposits from Water Treatment Waste towards Catalytic Chemical Syntheses

The toxicity and persistence of heavy metals has become a serious problem for humans. These heavy metals accumulate mainly in wastewater from various industries’ discharged effluents. The recent trends in research are now focused not only on the removal efficiency of toxic metal particles, but also on their effective reuse as catalysts. This review discusses the types of heavy metals obtained from wastewater and their recovery through commonly practiced physico-chemical pathways. In addition, it covers the advantages of the new system for capturing heavy metals from wastewater, as compared to older conventional technologies. The discussion also includes the various structural aspects of trapping systems and their hypothesized mechanistic approaches to immobilization and further rejuvenation of catalysts. Finally, it concludes with the challenges and future prospects of this research to help protect the ecosystem.