Recovery of 1,4‐Dimethyl Piperazine from Aqueous Solutions Using Polymeric Adsorbent and Ion‐Exchange Resins

Abstract

Strong and weakly acidic ion exchange resins and polymeric adsorbents are used for recovery of 1,4‐dimethyl piperazine (DMP) from aqueous solutions. Sorption of the amine in undissociated form is the primary mechanism of uptake of DMP on the ion‐exchange resins. Equilibrium adsorption data for DMP on the resins, at various temperatures, are fitted in Langmuir adsorption isotherm. Kinetic studies show that intraparticle diffusional resistance controls the sorption of DMP into the resin matrix. A mathematical model based on intraparticle diffusion and external mass transfer is used for simulating breakthrough profiles and compared with the experimental results for a fixed bed of weakly acidic Indion‐652 resin. The DMP loaded bed of the resin was effectively regenerated with methanol.     

Application of Layered Double Magnesium–Aluminum Oxides for the Purification of Aqueous Solutions from Dyes

Theoretical Foundations of Chemical Engineering - The possibility of purifying aqueous solutions from dyes with the use of layered double magnesium–aluminum oxides is studied. Using stamp ink...     

Fixed‐Bed Removal of Free and Complexed Ni from Synthetic and Industrial Aqueous Solutions

Abstract

This paper evaluates the application of several biosorbents for Ni removal from aqueous solutions in the absence and in the presence of EDTA. Fixed bed experiments were performed (Ni influent concentration, 2 mg dm^?3; EDTA doses, 0, 5, and 10 mg dm^?3; pH=7) to study the process feasibility as refining after conventional physicochemical treatment. In absence of EDTA, uptake capacity followed the order peat > Posidonia oceanica > chitosan > chitin ? Scharlau AC. Maximum uptakes of 8.95 mg g^?1 and 5.10 mg g^?1 were found for peat and Posidonia oceanica, respectively. In the presence of EDTA, removal capacity decreased for all biosorbents; Ni was detected in the effluent from the beginning of the operation, indicating low ability to retain Ni EDTA‐complexes. Activated carbon presented the ability to remove complexed Ni. Peat exhibited the best performance for the treatment of an industrial spill from a metal‐finishing facility, with effluent Ni concentration lower than 0.2 mg dm^?3 for more than two weeks of treatment (3500 pore volumes of treated wastewater).     

Liquid–Liquid Extraction of Butanol from Dilute Aqueous Solutions Using Soybean-Derived Biodiesel

Liquid–liquid extraction (LLE) of mixtures of butanol, 1,3-propanediol (PDO), and ethanol was performed using soybean-derived biodiesel as the extractant. The composition of the mixtures simulated the product of the anaerobic fermentation of biodiesel-derived crude glycerol, which has recently been reported for the first time by the authors. Using a biodiesel: with an aqueous phase volume ratio of 1:1, butanol recovery ranged from 45 to 51% at initial butanol concentrations of 150 and 225 mM, respectively. Less than 10% of the ethanol was extracted, and essentially no PDO was extracted. The partition coefficient for butanol in biodiesel was determined to be 0.91 ± 0.097. This partition coefficient is less than that of oleyl alcohol, which is considered the standard for LLE. However, butanol is suitable for blending with biodiesel, which would eliminate the need for separating the butanol after extraction. Additionally, biodiesel is much less costly than oleyl alcohol. If biodiesel-derived glycerol is used as the feedstock for butanol production, and biodiesel is used as the extractant to recover butanol from the fermentation broth, production of a biodiesel/butanol fuel blend could be a fully integrated process within a biodiesel facility. This process could ultimately help reduce the cost of butanol separation and ultimately help improve the overall economics of butanol fermentation using renewable feedstocks.     

Applications of the Biosorption Process for Nickel Removal from Aqueous Solutions – A Review

Wastewaters and contaminants released to the aqueous environment increase due to developing industrialization and technology. These wastewaters should be treated before being discharged to water bodies. Also, reusable materials in wastewaters must be recovered by appropriate techniques. Discharge limits required by the authorities become more stringent with updated legislations. Nickel ions can be reusable by recovering it after the biosorption process. So, this will prevent the loss of raw materials in industries and it also affects the economy in a positive way. Conventional heavy metal removal processes may be costly and inadequate to meet the desired discharge limits and they exhibit low efficiencies. Eco-friendly and economical treatment technologies gain great importance in the removal and recovery of nickel from wastewaters. In this study, biosorption which is the subject of numerous studies and one of the heavy metal removal methods will be investigated, and nickel removal by this technique and the biosorption mechanism will also be elaborated with data from literature studies.     

High Performance of UiO-66 Metal–Organic Framework Modified with Melamine for Uptaking of Lead and Cadmium from Aqueous Solutions

Journal of Inorganic and Organometallic Polymers and Materials - In this paper, UiO-66 metal–organic framework (MOF) was prepared by a hydrothermal method and modified consequently with...     

Pseudo‐Hydroxide Extraction in the Separation of Sodium Hydroxide from Aqueous Solutions Using Alkyl Phenols

Abstract

Pseudo‐hydroxide extraction of sodium hydroxide from aqueous solution using four alkyl phenols of nearly identical molecular weight in 1‐octanol at 25°C was examined to understand the effect of alkyl substituents. The order of extraction strength among the four alkyl phenols tested was 4‐tert‐octylphenol>3,5‐di‐tert‐butylphenol>2,4‐di‐tert‐butylphenol>2,6‐di‐tert‐butyl‐4‐methylphenol. A good correlation with phenol pK _a was observed, indicating that extraction strength is determined by phenol acidity, as modified by steric effects in proximity to the phenol –OH group. The effective partition ratios (P _eff) of two phenols from 1 M NaOH solution were determined, showing that the phenols remain predominantly in the 1‐octanol phase even when converted to their sodium salts. However, the hydrophobicity of the tested phenols may not be sufficient for process purposes. The equilibrium constants for the governing extraction equilibria were determined by modeling the data using the program SXLSQI, supporting the cation‐exchange extraction mechanism. The proposed mechanism consists of two simple sets of equilibria for

1. Ion‐pair extraction to give Na⁺OH^? ion pairs and corresponding free ions in 1‐octanol the phase and

2. Cation exchange by monomeric phenol molecules (HAs) to form monomeric organic‐phase Na⁺A^? ion pairs and corresponding free organic‐phase ions.

PEG Modification Effect of Silica on the Suzuki–Miyaura Coupling Reaction Using Silica-immobilized Palladium Catalysts

Abstract  

The Pd phosphine complex catalysts immobilized onto polyethylene glycol (PEG)-modified silica were prepared in order to clarify the effect of the PEG modification on the Suzuki–Miyaura coupling reaction in organic solvents. For the reaction of ethyl p-bromobenzoate and phenylboronic acid in the presence of potassium carbonate in toluene, the PEG-modified silica-immobilized Pd catalysts exhibited much higher activities than the catalysts without PEG modification.     

Reverse Precipitation Synthesis of ≤ 10 nm Magnetite Nanoparticles and Their Application for Removal of Heavy Metals from Water

Silicon - Fe3O4 nanoparticles having size ≤ 10nm were prepared by reverse co-precipitation method. This is a rapid, simple, and cost-effective (only one Fe-salt is used) synthesis route...     

Preparation and Adsorption Properties of λ-MnO2-Cellulose Hybrid-Type lon-Exchanger for Lithium Ion. Application to the Enrichment of Lithium Ion from Seawater

Abstract

spherical beads of a hybrid-type ion-exchanger (HIE) have been prepared by dispersing microcrystalline λ-MnO2 in macroporous cellulose gel beads. The beads were 0.1 to 0.3 mm in diameter and contained 0.71 g λ-MnO2/g dry HIE. The ion-exchange behaviors of HIE for lithium and sodium ions were investigated by batch and column methods. The uptakes for lithium and sodium ions were 2.8 and 0.1 mmol/g dry HIE, respectively, at pH 12.3 by the batch method and 1.0 and 0.1 mmol/g dry HIE at pH 11.6-11.8, respectively, by the column method. When 1.52 L seawater was passed through a column containing 0.05g wet HIE at a flow rate of 0.3 mL/min, 2.0 mg lithium/g dry HIE was recovered, indicating that the enrichment ratio for lithium ion was 1.3 × 10⁴ mL/g and the enrichment factors for lithium ion to sodium, potassium, calcium, and magnesium ions were 7.1 × 10⁴, 1.7 × 10³, 1.0 × 10³, and 6.9 × 10³, respectively.     

Equilibria and Kinetics of Extraction of Citric Acid from Aqueous Solutions in Alamine 336–Cyclohexanone System

Abstract

Equilibria and kinetics for the extraction of citric acid by Alamine 336 in cyclohexanone as diluent are reported. The theory of extraction accompanied by a chemical reaction has been used to obtain the intrinsic kinetics of extraction of citric acid by Alamine 336 in cyclohexanone. The reaction has been found to be first order in both Alamine 336 and citric acid with a rate constant of 8.8×10^?3 m³ kmol^?1 s^?1.     

Preparation and Characterization of Nano-Sized Iron–Titanium Mixed Oxide for Removal of Some Lanthanides from Aqueous Solution

Nano-structured iron(III)–titanium(IV) mixed oxide, Fe–O–Ti, was prepared by co-precipitation technique and characterized using Transmission Electron Microscopy, Fourier Transform Infra Red, Energy Dispersive X-ray spectroscopy, and Thermal Analysis. The particle size of the prepared material was found to be 10–15 nm. The sorptive potential of nano-composite, Fe–O–Ti, for the removal of some lanthanide elements (including, Ce, Nd, and Gd) was assessed in this work. The percent uptake was found to be 95.6%, 89.5, and 81.9 for Ce³⁺, Nd³⁺, and Gd³⁺ ions, respectively. Three kinetic models, pseudo-first-order, pseudo-second-order, and intra particle diffusion models, were tested. The results indicated that the pseudo-second-order model is more applicable for the sorption process. The experimental equilibrium data were tested for the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models; it was well predicted by the Freundlich model. The thermodynamic parameters were calculated. The results indicated that the nano-sized iron-titanium mixed oxide can be considered as a promising material for the removal of some lanthanides from aqueous solution.     

Inorganic–Organic Hybrid Materials of Zirconium and Aluminum and Their Usage in the Removal of Methylene Blue

Two novel inorganic–organic hybrid materials, Al-Pydca-3-APDEMS-H and Zr-Pydca-3-APDEMS-H, were prepared by the sol gel method in two steps. In the first step, Al(O^sBu)₂-Pydca and Zr(OPrⁿ)₃-Pydca complexes were prepared from the reactions of aluminum sec-butoxide Al(O^sBu)₃ and zirconium n-propoxide Zr(OPrⁿ)₄ with 2,6-pyridinedicarboxylic acid, respectively. After 3 h of stirring, 3-aminopropyldiethoxymethyl silane (3-APDEMS) and dilute hydrochloric acid were added to the Al(O^sBu)₂-Pydca and Zr(OPrⁿ)₃-Pydca mixtures to hydrolyze the reactions and to form condensation products. These hybrid products were characterized by a combination of Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray (EDX) spectroscopy, Brunauer–Emmett–Teller (BET) analysis, Barrett-Joyner-Halenda (BJH) and other analysis methods. These hybrid materials were used for the removal of methylene blue (MB), a cationic organic dye. The removal efficiency of hybrid materials was measured by UV–Vis spectroscopy.

     

Fabrication of Poly（y-glutamic acid）-coated Fe3O4 Magnetic Nanoparticles and Their Application in Heavy Metal Removal

In this study, poly（y-glutamic acid）-coated Fe3O4 magnetic nanoparticles （y-PGA/Fe304 MNPs） were successfully fabricated using the co-precipitation method. Fe3O4 MNPs were also prepared for comparison. The av erage size and specific surface area results reveal that 7-PGA/Fe304 MNPs （52.4 nm, 88.41 m2.g-1） have smaller particle size and larger specific surface area_ than Fe3O4 MNPs （62.0 nm, 76.83 mLg-1）. The y-PGA/Fe3O4 MNPs     

Evaluation of the Effect of Nanosilica on Thermal and Mechanical Properties of Metal–Metal and Metal–Glass Canola-Based Polyurethane/Nanosilica Adhesives

Nanocomposites with different concentration of nanofiller were prepared by adding nanosilica to the canola-based polyurethane matrix via in situ polymerization. The effect of nanosilica on the mechanical properties of adhesives was evaluated by tensile tests. Adhesive characteristics on metal–metal and metal–glass bondings were also evaluated by lap shear strength tests. Incorporation of nanosilica into the canola-based polyurethane enhanced both tensile and lap shear strength of synthesized adhesives. Also the effect of nanoparticles on glass transition temperature and thermal stability was investigated by differential scanning calorimetry and thermogravimetric analysis, respectively. The increase of nanosilica content in the polyurethane adhesives, thermal property of the nanocomposites improved.     

Investigation of Selectivity and Kinetic Behavior of Strong‐Base Ion Exchange Resin Purolite A 520E for Nitrate Removal from Aqueous Solution

Abstract

The aim of this work is to present experimental results on the removal of nitrate by nitrate selective ion exchange resin, Purolite A 520E. The resin particle size, nitrate concentration, temperature, and stirring speed were investigated as experimental parameters and the optimum conditions for nitrate removal were determined. Nitrate removal by strong base anion exchange resin Purolite A 520E was carried out with the batch method in the presence of chloride and sulfate ions. The existence of a high concentration of competing ions in a solution resulted in a reduction of nitrate removal. Nitrate removal ratios decreased from 98% to 85% and 88%, respectively, in the presence of chloride and sulfate ions when the chloride and sulfate ratios were increased in solution. The process kinetics were predicted by using Homogenous Diffusion Models. It was seen that about 98% of nitrate in the aqueous solution could be removed using optimum conditions.