用海藻类生物吸附剂去除废水中的重金属离子——一种经济型新技术

Heavy metal pollution from industrial wastewater is a worldwide environmental issue. Biosorption of heavy metals by using biosorbents derived from various types of biomass has been shown to be effective for the uptake of heavy metal ions. In this study, biosorbents derived from the biomass of a group of marine macroalgae were used for the removal and recovery of heavy metal ions from aqueous solutions. Results indicated that the biosorbents have high uptake capacities and affinities for a number of heavy metal ions. The uptake capacities of the biosorbents were in the range of 1.0 to 1.5mmol·g-1 for divalent heavy metal ions. The kinetics of the uptake process was fast and the process can be used in both batch and fixed-bed operations. It appears that the biosorption process by using biosorbents from marine macroalgae can be an efficient and cost effective technology for the treatment of heavy metal containing wastewater.     

二（2-乙基已基）磷酸萃取氨基苯甲酸的平衡特性

A series of extraction equilibrium experiments for aminobenzoic acid with di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane or 1-octanol was carried out. The effects of aminobenzoic acid concentration,D2EHPA concentration and pH on the distribution ratio were discussed in detail. The infrared spectra of the organic phase loaded with solute illustrated that pH had little effect on the structure of the complex formed. There proceed ion association and cation-exchange.reaction in the extraction. An expression of the equilibrium distribution was proposed.     

Emulsion liquid membrane for selective extraction of Bi(III)

Di(2-ethylhexyl)phosphoric acid was used as extractant of bismuth ions from nitrate medium by emulsion liquid membrane, with Triton X-100 as the biodegradable surfactant in n-pentanol bulk membrane. The novelties and innovative points of this work are the application of emulsion liquid membrane for selective and efficient extraction of bismuth ions as wel as the relevant optimization procedures. The extraction of bismuth ions was evaluated by the yield of extraction. The experimental parameters were evaluated and optimized, including the ratio of di(2-ethylhexyl)phosphoric acid mass concentration to Triton X-100 (1.0%:0.5%), nature of diluent (n-pentanol), nature and concentration of stripping solution (sulfuric acid, 0.5 mol·L?1), stirring speed (1800 r·min?1) and equilibrium time of extraction (20 min), initial feed solution of bismuth (350 mg·L?1) and the volume ratio of internal stripping phase to membrane phase (14). The experimental parameters of kinetic extraction reveal that the bismuth ions can be extracted by 100%.     

The kinetic analysis of optimization and selective transportation of Cu(Ⅱ) ions with TNOA as carrier by MDLM system

This study covers the transportation of Cu(Ⅱ) ions by multi-dropped liquid membrane(MDLM) system and tri-noctylamine(TNOA) as carrier in kerosene. Batch experiments are held to obtain optimum conditions for the transportation of Cu(Ⅱ) ions such as volume of donor, organic, and acceptor phase 100 ml, p H of donor phase9.00, temperature 298.15 K, concentration of H_2SO_4 in acceptor phase 1.00 mol·L~(-1), concentration of TNOA in organic phase 5.00 × 10~(-3)mol·L~(-1)and rate of peristaltic pump 50 ml·min~(-1). Optimum circumstances of this extraction are as follows: p H of donor phase is 9.00, concentration of TNOA is 5.00 × 10~(-3)mol·L~(-1),1.00 mol·L~(-1)H_2SO_4 as acceptor phase, and flux rate is 50 ml·min~(-1). Cu(Ⅱ) ion transportation is consecutive first order irreversible reaction. Activation energy is found as 5.22 kcal·mol-1(21.82 k J·mol~(-1), this process is called as diffusion controlled system. Selective transportation of Cu(Ⅱ) ions with alkaline, alkaline earth, and different heavy metal ions at optimum conditions of single Cu(Ⅱ) extraction was conducted. According to the selective transportation Cu(Ⅱ) ions with alkaline and alkaline earth metal ions, Na~+, K~+, and Ba~(2+)ions are not detected in the acceptor phase, but 12.00% of Ca~(2+)ions is transported from donor phase to acceptor phase. At the end of the simultaneous extraction of Zn(Ⅱ), Fe(ⅡI), and Mo(VI) with Cu(Ⅱ) ions, 2.20% of Mo(VI), 0.80% of Fe(Ⅲ) and 3.60% of Zn(Ⅱ) are detected in the acceptor phase.     

铟、镓、铊金属离子通过色谱纤维支撑固态膜的传递行为(英文)

The transport of metal ions of indium, gallium and thallium from source solution to receiving phase through the chromatographic fiber supported solid membrane in the acetylacetone (HAA) containing mixed solvent system has been explored. The fibers supported solid membranes were prepared with chemical synthesis from cellulose fibers and citric acid with the carboxylic acid ion exchange groups introduced. The experimental variables, such as concentration of metal ions (10-2 to 10-4 mol·L-1) in the source solu...     

Solvent extraction of lanthanum and cerium ions from hydrochloric acidic aqueous solutions using partly saponified 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester

In order to clarify the extraction process with saponified extractant, the solvent extraction experiments of rare earth elements(REEs), lanthanum and cerium, by using partly saponified 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester(EHEHPA, HL) from hydrochloric acidic solutions have been performed. The concentration of initial aqueous rare earth ion was in a range of 0.0010–0.1000 mol·L~(-1); EHEHPA in a range of 0.2877–0.8631 mol·L~(-1) with saponification rate of 0.3(mole fraction), and the initial aqueous p H in a range of 1.00–4.00. Firstly, the extracted species were determined by the saturation extraction capacity method. Secondly, according to the equilibrium aqueous pH values, the extraction processes were divided into three different categories: extraction with saponified EHEHPA, extraction with un-saponified EHEHPA, and hydrolysis process. Finally, for the first two processes, in order to predict the distribution ratio, two semi-empirical calculation models were developed with.The calculation results are in good agreement well with the experimental data.     

菌丝体-甲壳素水处理剂对重金属离子吸附性能的研究

The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions were studied.The result shows that the chitin adsorbent has high adsorption capacity for many heavy metal ions and Ni^2 in citric acid.The influence of pH was significant:When pH is higher than 4.0,the high adsorption capacity is obtained.otherwise H^ ion inhibits the adsorption of heavy metal ions.The comparison of the chitin adsorbent with some other commercial adsorbents was made,in which that the adsorption behavior of chitin adsorbent is close to that of commercial cation exchange adsorbents,and its cost is much lower than those commercial adsorbents.     

Ghezeljeh nanoclay as a new natural adsorbent for the removal of copper and mercury ions:Equilibrium,kinetics and thermodynamics studies

Heavy metal determination was carried out by applying the solid phase extraction (SPE) method in batch mode followed by atomic absorption spectroscopy (AAS) and inductively coupled plasma atomic emission spectrosco-py (ICP-AES) from aqueous solutions using Ghezeljeh montmoril onite nanoclay as a new natural adsorbent. The Ghezeljeh clay is characterized by using Fourier Transform Infrared (FT-IR) Spectroscopy, Scanning Electron Mi-croscopy–Energy Dispersive Spectrometry (SEM–EDS) and X-ray Diffractometry (XRD) and X-ray Fluorescence (XRF). The results of XRD and FT-IR of nanoclay confirm that montmoril onite is the dominant mineral phase. Based on SEM images of Ghezeljeh clay, it can be seen that the distance between the plates is Nano. The effects of varying parameters such as initial concentration of metal ions, pH and type of buffer solutions, amount of ad-sorbent, contact time, and temperature on the adsorption process were examined. The effect of various interfer-ing ions was studied. The adsorption data correlated with Freundlich, Langmuir, Dubinin–Radushkevich (D–R), and Temkin isotherms. The Langmuir and Freundlich isotherms showed the best fit to the equilibrium data for Hg(I ), but the equilibrium nature of Cu(II) adsorption has been described by the Langmuir isotherm. The kinetic data were described with pseudo-first-order, pseudo-second-order and double-exponential models. The adsorp-tion process follows a pseudo-second-order reaction scheme. Calculation ofΔG0,ΔH0 andΔS0 showed that the nature of Hg(II) ion sorption onto the Ghezeljeh nanoclay was endothermic and was favored at higher temper-ature, and the nature of Cu(II) ion sorption was exothermic and was favored at lower temperature.     

Recovery of nickel,cobalt, copper and zinc in sulphate and chloride solutions using synergistic solvent extraction

A number of synergistic solvent extraction (SSX) systems have been developed to recover nickel, cobalt, zinc and copper from sulphuric and chloride leach solutions by the solvent extraction team of CSIRO, Australia. These in-clude (1) Versatic 10/CLX50 system for the separation of Ni from Ca in sulphate solutions, (2) Versatic 10/4PC system for the separation of Ni and Co from Mn/Mg/Ca in sulphate solutions, (3) Cyanex 471X/HRJ-4277 system for the separation of Zn from Cd in sulphate solutions, (4) Versatic 10/LIX63 system for the separation of Co from Mn/Mg/Ca in sulphate solutions, (5) Versatic 10/LIX63/TBP system for separation of Ni and Co from Mn/Mg/Ca in sulphate solutions, (6) Versatic 10/LIX63 system for the separation of cobalt from nickel in sulphate solutions by difference in kinetics, (7) Cyanex 272/LIX84 system for the separation of Cu/Fe/Zn from Ni/Co in sulphate solutions, (8) Versatic 10/LIX63/TBP system to recover Cu/Ni from strong chloride solutions, and (9) Versatic 10/LIX63 system to separate Cu from Fe in strong chloride solutions. The synergistic effect on metal separation and efficiency is presented and possible industrial applications are demonstrated. The chemical stability of selected SSX systems is also reported.     

Investigation of extraction fraction in confined impinging jet reactors for tri-butyl-phosphate extracting butyric acid process☆

The extraction fraction E and overall volumetric mass transfer coefficient kLa of TBP extracting butyric acid pro-cess in confined impinging jet reactors (CIJR) with two jets were investigated. The main variables tested were the concentration of tri-butyl-phosphate (TBP) and butyric acid, the impinging velocity V, the impinging velocity ratio of two phases Vorg/Vaq, the nozzle inner diameter di and the distance L between the jet axes and the top wall of the impinging chamber. The results showed that E and kLa increase with an increase of the impinging ve-locity V, the concentration of TBP Corg, and the impinging velocity ratio Vorg/Vaq. However, E and kLa decrease with an increase of the inner diameter di from 1 to 2 mm, the concentration of butyric acid Caq from 0.5%(v/v) to 2%(v/v). The factor L ranging from 3 to 11 mm has a negligible effect on E and kLa. A correlation on these variables and kLa was proposed based on the experimental data. These results indicated good mass transfer performance of CIJR in the extraction operation.     

Synergistic Effects in the Extraction of Uranium(VI) by Di-4-octylphenyl Phosphoric Acid

Abstract

The extraction of uranium(VI) from sulfuric acid solutions by di-4-octylphenyl phosphoric acid (DOPPA) is enhanced by the addition of neutral organophosphorus compounds due to synergistic action. The effect of tri-n-butyl phosphate (TBP), dibutylbutyl phosphonate (DBBP), and tri-n-octyl phosphine oxide (TOPO) was studied. The synergistic effect increased in this order. In the case of TBP and DBBP the extraction coefficient for U(VI) decreased with increasing concentration of synergistic agent after reaching a maximum. With TOPO, on the other hand, there was an increase even after this limit. This was because of the extraction of uranium by TOPO itself. The effect of uranium loading in the organic phase on the synergistic behavior was studied and the results were compared with those obtained with di-2-ethylhexyl phosphoric acid (DEHPA) in the presence of the same synergistic agents. The results with these two extractants indicate that with TOPO the synergism is mainly due to the formation of substitution products of the type UO₂A₂B₂ and with TBP addition products of the type UO₂(HA₂)₂B.     

Manganese extraction with mixtures of bis(2,4,4-trimethylpentyl)dithiophosphinic acid and trioctyl phosphine oxide

It was shown that a strong synergistic effect (S ≈ 4000) takes place when extracting manganese (II) from sulfate solutions with mixtures of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (CYANEX 301) and trioctyl phosphine oxide (TOPO. The synergistic effect is caused by the formation of the mixed complex Mn-HR-TOPO. Analysis of the manganese partition between organic and aqueous phase as well as of the IR and electron paramagnetic resonance spectra of the extracts showed that manganese forms a hexacoordinated complex with the dithiophosphinate ions and TOPO with an octahedral geometry. The composition of the complex can be presented as MnR₂?2TOPO.

Examples of the possible use of the CYANEX 301 and trialkyl phosphine oxide (TAPO, CYANEX 923) mixtures when processing manganese-containing liquors are given.     

CYANEX 923 AS AN EXTRACTANT FOR TRIVALENT LANTHANIDES AND YTTRIUM

ABSTRACT

The extraction of yttrium and some trivalent lanthanides from thiocyanate and nitrate solutions using Cyanex 923 { TRPO ) in xylene as an extractant has been investigated. It has been found that these trivalent metal ions are extracted from thiocyanate solution as M(SCN)₃.n TRPO ; n in general having the values of 4 and 3 for the lighter and the heavier lanthanides respectively. On the other hand, from nitrate solutions these trivalent metal ions are extracted as M(NO₃)₃ 3 TRPO. The equilibrium constants of the extracted complexes have been obtained by non-linear regression analysis. In both the thiocyanate and nitrate systems, the distribution ratios of trivalent lanthanides are found to increase with decreasing ionic radii and the distribution ratio of yttrium lies along with those of the middle lanthanides. The separation factors between these trivalent metal ions were evaluated and compared with those obtained using commercially important extraction reagents like tributylphosphate (TBP), trioctylphosphine oxide (TOPO) and di-2-ethylhexylphosphoric acid (DEHPA). The separation possibilities between yttrium and the trivalent lanthanides have also been discussed.     

Use of mixtures based on organophosphorous acids for the extraction of vanadium(IV) from model and industrial sulfurous solutions

We investigated the distribution of vanadium(IV) during extraction from model and actual technological sulfurous solutions by the organophosphorous acids di(2-ethylhexyl)phosphoric acid (DEHPA) and di(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) using various solvents. We determined the most effective organic and organomineral mixtures for the extraction of vanadium(IV) from model and technological solutions of aqueous leach of used vanadium catalysts.     

二（2—乙基己基）硫代磷酸的合成

研究了新型萃取剂二(2-乙基己基)硫代磷酸的合成、纯化及结构鉴定。     

EXTRACTION OF RARE EARTH METALS WITH 2-ETHYLHEXYL PHOSPHONIC ACID MONO-2-ETHYLHEXYL ESTER IN THE PRESENCE OF DIETHYLENETRIAMINEPENTAACETIC ACID IN AQUEOUS PHASE

Abstract

The extraction equilibria of rare earth metals with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (commercial name, PC-88A, henceforth abbreviated as HR) dissolved in n-heptane were measured at 303 K. It was found that rare earth metals are extracted with the dimer of the extractant, (HR)₂, as follows.

The extraction equilibrium constants of metals were obtained and compared with the extraction equilibrium constants obtained by di(2-ethylhexyl)phosphoric acid (henceforth D2EHPA).

Furthermore, the extraction equilibria of rare earth metals with PC-88A in the presence of diethylenetriaminepentaacetic acid (henceforth DTPA) in an aqueous phase were also measured to discuss the effect of DTPA on the extraction of rare earth metals.     

Separation and Recovery of Silver(I) Ions from Base Metal Ions by Melamine‐formaldehyde‐thiourea (MFT) Chelating Resin

Abstract

Melamine‐formaldehyde‐thiourea (MFT) chelating resin were prepared using melamine (2,4,6‐triamino‐1,3,5‐triazine), formaldehyde, and thiourea and this resin has been used for separation and recovery of silver(I) ions from copper(II) and zinc(II) base metals and calcium(II) alkaline‐earth metal in aqueous solution. The MFT chelating resin was characterized by elemental analysis and FT‐IR spectra. The effect of pH, adsorption capacity, and equilibrium time by batch method and adsorption, elution, flow rate, column capacity, and recovery by column method were studied. The maximum uptake values of MFT resin were found as 60.05 mg Ag⁺/g by batch method and 11.08 mg Ag⁺/g, 0.052 mg Zn²⁺/g, 0.083 mg Cu²⁺/g and 0.020 mg Ca²⁺/g by column method. It was seen that MFT resin showed higher uptake behavior for silver(I) ions than base and earth metals due to chelation.     

Characterization and adsorption behavior of newly synthesized sodium bis(2-ethylhexyl) sulfosuccinate–cerium (IV) phosphate (AOT–CeP) cation exchanger

A new cationic exchange material, sodium bis(2-ethylhexyl) sulfosuccinate (AOT) with cerium (IV) phosphate (AOT–CeP) has been synthesized. The characterization of the ion exchanger was performed by using infra red spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo gravimetric analysis/differential thermo gravimetric analysis (TGA/DTA/DTG) and elemental analysis. The ion exchange properties like ion exchange capacity, elution and concentration behavior of AOT–CeP were determined by taking the material into a column and elution of H⁺ was done by NaNO₃. The thermal stability of the ion exchanger was studied by determining ion exchange capacity after heating to different temperatures for one hour. The adsorption studies on AOT–CeP demonstrated that the material is selective for Cu²⁺, Pb²⁺, Cd²⁺, Zn²⁺ and Hg²⁺ ions. AOT–CeP was found to be effective for the separation of Cu²⁺, Pb²⁺, Cd²⁺, Zn²⁺ and Hg²⁺ ions in the presence of alkali metals/alkaline earth metals. This cationic exchanger was also effective for the removal of Cu²⁺, Pb²⁺, Cd²⁺, Zn²⁺ and Hg²⁺ ions in the presence of acid and other transition metal ions. Thus, AOT–CeP can be used for the removal of these ions from the waste water during its treatment.     

Improved kinetics-based gold cyanide extraction with mixture of LIX79+TOPO utilizing hollow fiber membrane contactors

Dispersion-free solvent extraction of gold(I) (Au(CN)₂⁻) from alkaline cyanide media was performed using porous hydrophobic hollow fibers with mixtures of membrane extractants. The organic extractant used for gold(I) extraction was LIX79 (N,N′-bis(2-ethylhexyl)guanidine) alone and a mixture of trioctylphosphine oxide (TOPO)+LIX79 diluted with n-heptane. The mixture of LIX79+TOPO affords a better performance than LIX79 alone. It took 300 s to extract more than 95% gold with equimolar LIX79+TOPO (0.125 M), whereas pure LIX79 (0.375 M) took 1860 s to reach the same percentage level of gold extraction (over six times slower). The mass transfer coefficient’s (K_Au^E) value was around four times higher with the equimolar mixture of 0.125 M LIX79+0.125 M TOPO than with LIX79/n-heptane alone. Extraction of Au(CN)₂⁻ from alkaline cyanide solutions with TOPO alone was also observed, indicating that gold(I) complexation takes place probably by a solvation reaction mechanism (M⁺Au(CN)₂·S_n). A model is presented which describes the extraction mechanism, indicating different rate-controlling steps. The validity of this model was evaluated with experimental data and was found to tie in well with theoretical values.     

Recovery of zinc,cadmium and mercury (ii) from chloride and sulphate media by solvent extraction

The extraction of zinc, cadmium and mercury from chloride and sulphate media by solvating extractants, liquid anion and liquid cation exchangers has been reviewed both from the literature and by experiment. The results have been discussed in terms of both practical process possibilities and the use of slope analysis to identify the extracted species. These show that slope analysis cannot give positive unambiguous identification of extraction stoichiometry in systems in which the extracted metal species contains coordinating ligands from the aqueous phase. However, in the extraction of Zn and Cd from sulphate media by di(2-ethylhexyl)phosphoric acid (DEHPA) the extracted species is shown to be an MR₂(HR)₂ monomer by slope analysis demonstrating its use in simple systems. In the case of amines and solvating reagents such as TBP^c and TOPO zinc appears to be extracted from Cl^– media as either ZnCl₂ or sometimes HZnCl₃ whereas Cd and Hg(II) appear to be always extracted as HCdCl₃ and HHgCl₃ species. The use of aqueous phase complexing by Cl^– to improve the separation of Zn and Cd by extraction is clear. Some results are presented for the recovery of zinc from sulphate media by oximes and mercury from sulphuric acid media by amines and DEHPA.