Preparation of porous PMMA/Na–montmorillonite cation-exchange membranes for cationic dye adsorption

Porous PMMA/Na⁺–montmorillonite (MMT) cation-exchange membranes were successfully prepared by entrapment method in this study. One approach (simple mixing) was to mix commercial PMMA polymer with Na⁺–MMT clays in solvent for membrane preparation (Membrane A). The other approach (emulsion polymerization) was to synthesize the PMMA/Na⁺–MMT polymer composite via emulsion polymerization first, followed by membrane casting (Membrane B for Kunipia F clays and Membrane C for PK-802 clays). Membrane morphology and properties were characterized. The thermogravimetric analysis (TGA) verified the near complete incorporation of feed Na⁺–MMT clays in the PMMA/Na⁺–MMT composite membranes, while X-ray diffractograms (WXRD) exhibited the slightly enlarged interlayer spacing of Na⁺–MMT. The range of cation-exchange capacity (CEC) was 9–32 μequiv./47 mm disc. For batch cationic dye adsorption, the best performance was achieved by Membrane B with feed Na⁺–MMT/MMA (M/P) ratio (w/w) = 0.5 and Membrane C with feed M/P = 0.6, where about 95% Methyl violet adsorption was attained in 2 h. The optimal desorption solution was 1 M KSCN in 80% methanol and its related dye desorption efficiency was 92%. In the flow process using one piece of 47 mm disc of Membrane B (M/P = 0.5), dye solution was recirculated for 6 h and ≥85% dye could be removed. Higher than 94% of dye was desorbed at 1 or 4 mL/min, and the membrane regenerability was proved by successfully performing three consecutive cycles.     

Contribution of cell-surface components to Cu2+ adsorption by Pseudomonas putida 5-x

The contribution of various cell-surface components to Cu²⁺ adsorption by a Gram-negative bacterium, Pseudomonas putida 5-x, that was isolated from local electroplating effluent with a high capability to accumulate heavy metal ions was studied. The cell superficial layer had a negative effect on Cu²⁺ adsorption of the bacterial cells. Cu²⁺ adsorption capacity of the separated cell envelopes was fivefold more than that of the intact cells, owing to the liberation of more and more binding sites during the separation process. Some main components in the cell envelope, such as the peptidoglycan (PEG) layer, outer membrane, and inner membrane, provide the capability for Cu²⁺ adsorption. The content of the components in the cell envelope is in the order inner membrane > outer membrane > PEG layer, and their Cu²⁺ adsorption capacity was in the order PEG layer > outer membrane > inner membrane. The total contribution of the separated PEG layer material to Cu²⁺ adsorption by the cell envelope was no more than 15%, and the outer membrane and inner membrane contributed about 30–35% and 25–30%, respectively. The relatively high phospholipid content in the outer membrane may be the major reason for the higher adsorption capacity of the outer membrane to Cu²⁺ and, hence, such a high Cu²⁺ adsorption capacity of P. putida 5-x cell envelope.     

Characterization of metal chelate methacrylate monolithic disk for purification of polyclonal and monoclonal immunoglobulin G

Dynamic binding capacity (DBC) of commercial metal-chelate methacrylate monolith-convective interaction media (CIM) was performed with commercial human immunoglobulin G (IgG) (Cohn fraction II, III). Monoliths are an attractive stationary phase for purification of large biomolecules because they exhibit very low back pressure even at high flow rates and flow-unaffected binding properties. Adsorption of IgG onto CIM-IDA disk immobilized with Cu²⁺, Ni²⁺ and Zn²⁺ were studied with Tris-acetate (TA), phosphate-acetate (PA) and MMA (MES, MOPS and acetate) buffer systems at different flow rates. Adsorption and elution of IgG varied with different buffers and adsorption of IgG was maximum with MMA buffer. Adsorption of human IgG from Cohn fractions (II, III) was high when Cu²⁺ was used as ligand. CIM-IDA disk showed dynamic binding capacity in the range of 14–16 mg/ml with Cu²⁺ and 7–9 mg/ml with Ni²⁺ for human IgG with MMA buffer. In the case of CIM-IDA-Zn²⁺ column, the binding capacity was only about 0.5 mg/ml of support. Different desorption strategies like lowering of pH and increasing of competitive agent were also studied to achieve maximum recovery. Chromatographic runs with human serum and mouse ascites fluid were also carried out with metal chelate methacrylate monolithic disk and the results indicate the potential of this technique for polyclonal human IgG and monoclonal IgG purification from complex biological samples.     

Pervaporation performance of PDMS-NiY zeolite hybrid membranes in the desulfurization of gasoline

PDMS-Ni²⁺Y zeolite hybrid membranes were fabricated and used for the pervaporation removal of thiophene from model gasoline system. The structural morphology, mechanical stability, crystallinity, and free volume characteristics of the hybrid membranes were systematically investigated. Molecular dynamics simulation was employed to calculate the diffusion coefficients of small penetrants in the polymer matrix and the zeolite. The effect of Ni²⁺Y zeolite content on pervaporation performance was evaluated experimentally. With the increase of Ni²⁺Y zeolite content, the permeation flux increased continuously, while the enrichment factor first increased and then decreased possibly due to the occurrence of defective voids within organic–inorganic interface region. The PDMS membrane containing 5.0 wt% Ni²⁺Y zeolite exhibited the highest enrichment factor (4.84) with a permeation flux of 3.26 kg/(m² h) for 500 ppm sulfur in feed at 30 °C. The effects of operating conditions on the pervaporation performance were investigated in detail. It has been found that the interfacial morphology strongly influenced the separation performance of the hybrid membrane, and it was of great significance to rationally modify the interfacial region in order to improve the organic–inorganic compatibility.     

Electric field-enhanced assembly of polyelectrolyte composite membranes

In this paper, a novel method was developed to enhance the assembly of polyelectrolyte composite membranes by inducing an electric field during electrostatic adsorption process. The hydrolyzed polyacrylonitrile (PAN) ultrafiltration (UF) membrane was placed in between a capacitor setup. The polyethyleneimine (PEI) was compulsorily assembled on the PAN support under the action of external electric force. Subsequently, the polyelectrolyte composite membranes were evaluated by pervaporation separation of water and alcohol mixture. The membrane obtained with only one PEI layer had a separation factor of 304 and a permeate flux of 512 g/m² h (75 °C) for pervaporation of 95 wt% ethanol–water mixture. An atomic force microscopy was also used to observe the microtopographical changes. The regularity of the membranes assembled by the new method was also improved in comparison with the membrane assembled by a dynamic layer-by-layer adsorption.     

含低聚醚链共价有机骨架薄膜材料的制备及其离子分离性能

用2,5-二(2-甲氧基-乙氧基)对苯二甲酰肼(BMTH)和1,3,5-三甲氧基-2,4,6-三甲酰基苯(TpOMe)缩聚,基于界面聚合法,在多孔三氧化二铝(AAO)基底上制备出一种二维共价有机骨架(COF)膜TpOMe-BMTH,并研究了所得膜材料对锂、镁离子的分离性能。结果显示,TpOMe-BMTH/AAO膜具有高的结晶性和良好的稳定性,并表现出优异的金属离子选择性,在LiCl(0.1 mol·L^-1)和MgCl₂(0.1 mol·L^-1)组成的二元混合离子体系中,对Li⁺/Mg²⁺的分离因子高达258。基于密度泛函理论的平面波赝势方法计算表明,材料孔道中的富氧低聚醚链对 Li⁺和 Mg²⁺的结合能分别为-282.69和-13.46 kJ·mol^-1,使材料表现出强的亲锂特性,促进了Li⁺沿着COF膜的一维孔道进行吸附扩散,最终实现锂、镁离子的高效分离。     

Multiplex sensor for detection of different metal ions based on on–off of fluorescent gold nanoclusters

In this study, a multiplex fluorescence sensor for successive detection of Fe³⁺, Cu²⁺ and Hg²⁺ ions based on “on–off” of fluorescence of a single type of gold nanoclusters (Au NCs) is described. Any of the Fe³⁺, Cu²⁺ and Hg²⁺ ions can cause quenching fluorescence of Au NCs, which established a sensitive sensor for detection of these ions respectively. With the introduction of ethylene diamine tetraacetic acid (EDTA) to the system of Au NCs and metal ions, a restoration of fluorescence may be found with the exception of Hg²⁺. A highly selective detection of Hg²⁺ ion is, thus, achieved by masking Fe³⁺ and Cu²⁺. On the other hand, the masking of Fe³⁺ and Cu²⁺ leads to the enhancement of fluorescence of Au NCs, which in turn provides an approach for successive determination of Fe³⁺ and Cu²⁺ based on “on–off” of fluorescence of Au NCs. Moreover, this assay was applied to the successful detection of Fe³⁺, Cu²⁺ and Hg²⁺ in fish, a good linear relationship was found between these metal ions and the degree of quenched fluorescent intensity. The dynamic ranges of Hg²⁺, Fe³⁺ and Cu²⁺ were 1.96 × 10⁻¹⁰–1.01 × 10⁻⁹, 1.28 × 10⁻⁷–1.27 × 10⁻⁶ and 1.2 × 10⁻⁷–1.2 × 10⁻⁶ M with high sensitivity (the limit of detection of Fe³⁺ 2.0 × 10⁻⁸ M, Cu²⁺ 1.9 × 10⁻⁸ M and Hg²⁺ 2 × 10⁻¹⁰ M). These results indicate that the assay is suitable for sensitive detection of these metal ions even under the coexistence, which can not only determine all three kinds of metal ions successively but also of detecting any or several kinds of metal ions.     

Heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel and its application to a flow analytical system using flame atomic absorption spectrometry

This study aimed to evaluate the heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel (CaAD) and incorporate this biosorbent into a flow analytical system for heavy metal ions using flame atomic absorption spectrometry (FAAS). The biosorbent was synthesized by electrostatically coating calcium alginate onto diethylenetriamine (dien)-silica gel. Copper ion adsorption tests by a batch method showed that CaAD exhibited a higher adsorption rate compared with other biosorbents despite its low maximum adsorption capacity. Next, CaAD was packed into a 1 mL microcolumn, which was connected to a flow analytical system equipped with an FAAS instrument. The flow system quantitatively adsorbed heavy metals and enriched their concentrations. This quantitative adsorption was achieved for pH 3–4 solutions containing 1.0 × 10⁻⁶ M of heavy metal ions at a flow rate of 5.0 mL min⁻¹. Furthermore, the metal ions were successfully desorbed from CaAD at low nitric acid concentrations (0.05–0.15 M) than from the polyaminecarboxylic acid chelating resin (Chelex 100). Therefore, CaAD may be considered as a biosorbent that quickly adsorbs and easily desorbs analyte metal ions. In addition, the flow system enhanced the concentrations of heavy metals such as Cu²⁺, Zn²⁺, and Pb²⁺ by 50-fold. This new enrichment system successfully performed the separation and determination of Cu²⁺ (5.0 × 10⁻⁸ M) and Zn²⁺ (5.7 × 10⁻⁸ M) in a river water sample and Pb²⁺ (3.8 × 10⁻⁹ M) in a ground water sample.     

金属螯合亲和膜吸附分离与纯化溶菌酶的研究(Ⅱ)──不同金属螯合亲和膜对溶菌酶的吸附性能

采用低温氧或氨等离子体法改性聚丙烯微孔膜,基于等离子体改性膜的活化、偶联及螯合过程的机理,制备了Fe³⁺,Ni²⁺,Cu²⁺和Zn²⁺等金属离子螯合亲和膜,并用于溶菌酶的吸-脱附实验.实验结果表明,Ni²⁺和Cu²⁺离子螯合亲和膜对溶菌酶具有较高的吸附量,螯合过程中采用氯化物盐溶液制得的膜对溶菌酶吸附量比采用硫酸盐溶液制得的膜的吸附量高.两种膜的重复吸-脱附性能相近,而Fe³⁺螯合亲和膜基本上不能用于重复吸-脱附实验.采用补充金属螯合离子,能部分恢复亲和膜对溶菌酶的吸附量,是实现亲和膜重复使用的有效方法.     

Application of hydroxy sodalite films as novel water selective membranes

Supported hydroxy sodalite (H-SOD) membranes were prepared on α-alumina disks using direct hydrothermal synthesis at 413 K for 3.5 h. The continuity of the membranes was verified using single gas permeation of He and N₂ at ambient conditions. The membranes were impermeable to N₂ and He, which validated absence of defects in the membrane structure. The membranes were used in dewatering several organic alcohol/water mixtures (organic alcohol being: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, and 2-pentanol). The influence of feed temperature (303–473 K), feed concentration (0–100 mol% alcohol in the feed), and absolute feed pressure (1.6–2.4 MPa) on the water flux were analyzed. The absolute feed pressure had no effect on the water permeance. The membrane exhibited a water/alcohol separation factor larger than 10⁶ and showed excellent thermal, mechanical, and operation stability in continuously dehydrating a water/ethanol mixture (72 mol% water) by pervaporation at 473 K and 2.2 MPa for 125 h. The normalized water flux correlated well with the water feed concentration for the primary alcohols. Below 40 mol% water in mixtures with secondary alcohols the water flux was three orders of magnitude lower. The water mobility through the membrane had an activation energy of ∼15 kJ/mol.     

Anodic alumina supported dual-layer microporous silica membranes

We present a new processing scheme for the deposition of microporous, sol–gel derived silica membranes on inexpensive, commercially available anodic alumina (Anodisk™) supports. In a first step, a surfactant-templated mesoporous silica sublayer (pore size 2–6 nm) is deposited on the Anodisk support by dip-coating, in order to provide a smooth transition from the pore size of the support (20 or 100 nm) to that of the membrane (3–4 Å). Subsequently, the microporous gas separation membrane layer is deposited by spin-coating, resulting in a defect-free dual-layer micro-/mesoporous silica membrane exhibiting high permeance and high selectivity for size selective gas separations. For example, in the case of CO₂:N₂ separation, the CO₂ permeance reached 3.0 MPU (1 MPU = 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹) coupled with a CO₂:N₂ separation factor in excess of 80 at 25 °C. This processing scheme can be utilized for laboratory-scale development of other types of microporous or dense inorganic membranes, taking advantage of the availability, low cost and low permeation resistance of anodic alumina (or other metal oxide) meso- and macroporous supports.     

A new beryllium ion-selective membrane electrode based on dibenzo(perhydrotriazino)aza-14-crown-4 ether

Beryllium(II) selective electrodes have been fabricated based on poly(vinyl chloride) (PVC) matrix membranes containing newly synthesized neutral carrier dibenzo(perhydrotriazino)aza-14-crown-4 ethers as ionophore. Best performance was exhibited by the membrane having a composition ionophore (IIa):PVC:sodium tetraphenylborate (NaTPB):tributyl phosphate (TBP) in the ratio (w/w; mg) of 5:30:3:65. This membrane worked well over a wide concentration range 7.6 × 10⁻⁶ to 1.0 × 10⁻¹ M of Be²⁺ with a Nernstian slope of 30.7 mV per decade of beryllium activity. The response time of the sensor is 15 s and the membrane can be used over a period of 4 months with good reproducibility. The proposed electrode works well in a wide pH range 3.0–9.0. It was successfully applied to the determination of beryllium in a mineral sample.     

Properties of PWA/ZrO2-doped phosphosilicate glass composite membranes for low-temperature H2/O2 fuel cell applications

Phosphosilicate doped with a mixture of phosphotungstic acid and zirconium oxide (PWA/ZrO₂–P₂O₂–SiO₂) was investigated as potential glass composite membranes for use as H₂/O₂ fuel cell electrolytes. The glass membranes were studied with respect to their structural and thermal properties, proton conductivity, pore characteristics, hydrogen permeability, and performance in fuel cell tests. Thermal analysis including TG and DTA confirmed that the glass was thermally stable up to 400 °C. The dependence of the conductivity on the humidity was discussed based on the PWA content in the glass composite membranes. The proton transfer in the nanopores of the PWA/ZrO₂–P₂O₅–SiO₂ glasses was investigated and it was found that a glass with a pore size of ∼3 nm diameters was more appropriate for fast proton conduction. The hydrogen permeability rate was calculated at various temperatures, and was found to be comparatively higher than for membranes based on Nafion^®. The performance of a membrane electrolyte assembly (MEA) was influenced by its PWA content; a power density of 43 mW/cm² was obtained at 27 °C and 30% relative humidity for a PWA/ZrO₂–P₂O₅–SiO₂ glass membrane with a composition of 6–2–5–87 mol% and 0.2 mg/cm² of Pt/C loaded on the electrode.     

Synthesis,characterization, aggregation and thermal properties of a novel polymeric metal-free phthalocyanine and its metal complexes

A novel polymeric metal-free phthalocyanine (M = 2H) and its metal complexes (M = Zn, Cu, Co and Ni) were prepared by the tetramerization reaction of 3,6,9-Tris(p-tolylsulfonyl)-1,11-bis(3,4-dicyanophenoxy)-3,6,9-triazaundecane 5 with the appropriate materials. The electrical conductivities of the metal-free phthalocyanine and the metal complexes, measured in air, were found to be ∼10⁻⁶–10⁻⁵ S m⁻¹. The aggregation property of the zinc complex 7 was investigated with Ni²⁺, Cu²⁺, Co²⁺, Pb²⁺, Cd²⁺ and Ag⁺ cations. Thermal analysis of the polymers were done by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) at a heating rate of 10 °C min⁻¹ under a nitrogen atmosphere. All the novel compounds were characterized by using elemental analysis, UV–Vis, FT–IR, NMR and MS spectral data and DSC, DTA/TG techniques.     

Novel potentiometric copper (II) selective membrane sensors based on cyclic tetrapeptide derivatives as neutral ionophores

Two novel membrane sensors sensitive and reasonably selective for Cu²⁺ ions are described. These are based on the use of newly synthesized cyclic tetrapeptide derivatives as neutral ionophores and sodium tetraphenylborate (NaTPB) as an anionic excluder in plasticized PVC membranes. The sensors exhibit fast and stable near-Nernstian response over the concentration range 1.0 × 10⁻⁶ mol l⁻¹ to 1.0 × 10⁻² mol l⁻¹ Cu²⁺ with a cationic slope of 30.2-25.9 mV per decade at pH 4.5-7 with a lower detection limit of 0.05-0.13 μg ml⁻¹. Effects of plasticizers, lipophilic salts and various foreign common ions are tested. The sensors display long life-span, long term stability, high reproducibility, and short response time. Selectivity of both sensors is significantly high for Cu²⁺ over Fe³⁺, Al³⁺, Zn²⁺, Cd²⁺, Hg²⁺, Ni²⁺, Co²⁺, Mn²⁺, alkaline earth and alkali metal ions. The sensors are used for direct measurement of copper content in different rocks and industrial wastewater samples from electroplating factories. The results agree fairly well with data obtained using atomic absorption spectrometry.     

Free-standing anion-exchange PEO–SiO2 hybrid membranes

Free-standing anion-exchange polyethylene oxide (PEO)–SiO₂ hybrid membranes with higher flexibility and good mechanical strength (tensile strength (TS) as high as 20.55 MPa) as well as high temperature tolerance (thermal degradation temperature in air, T_d, in the range of 220–240 °C) were prepared through sol–gel reaction of different precursors: charged alkoxysilane-functionalized PEO-1000 (PEO-[Si(OCH₃)₃]₂(+)), N-triethoxysilylpropyl-N,N,N-trimethylammonium iodine (A-1100(+)), monophenyltriethoxysilane (EPh) and in some cases also tetraethoxysilane (TEOS). Properties of the hybrid membranes, such as the thermal stability, tensile properties, hydrophilicity, and electrical performances, can be controlled by changing the feed ratio of the different sol–gel precursors. The results showed that some of the membranes have relatively good conductivity (∼0.003 S/cm) and so may find potential applications in alkaline membrane fuel cells.     

Synthesis and characterization of novel ion-imprinted polymeric nanoparticles for very fast and highly selective recognition of copper(II) ions

This work reports the preparation of new Cu²⁺ ion-imprinted polymeric nanoparticles using 1-hydroxy-4-(prop-2′-enyloxy)-9,10-anthraquinone (AQ) as a vinylated chelating agent. The Cu²⁺ ion found to form a stable 1:1 complex with AQ in methanol solution. The resulting Cu²⁺-AQ complex was copolymerized with ethyleneglycol dimethacrylate, as a cross-linking monomer, via precipitation polymerization method. The imprint copper ion was removed from the polymeric matrix using a 0.1 mol L⁻¹ HNO₃ solution. The Cu²⁺-imprinted polymeric nanoparticles were characterized by IR spectroscopy, scanning electron microscopy (SEM) and N₂ adsorption-desorption isotherms. The SEM micrographs showed colloidal nanoparticles of 60-100 nm in diameter and slightly irregular in shape. Optimum pH for maximum sorption was 7.0. Sorption and desorption of Cu²⁺ ion on the IIP nanoparticles were quite fast and achieved completely over entire investigated time periods of 2-30 min. Maximum sorbent capacity and enrichment factor of the prepared IIP for Cu²⁺ were 73.8 μmol g⁻¹ and 56.5, respectively. The relative standard deviation and limit of detection (C_LOD = 3S_b/m) of the method were evaluated as 2.6% and 0.1 ng mL⁻¹, using inductively coupled plasma-atomic emission spectrometry, respectively. It was found that the imprinting technology results in increased affinity of the prepared material toward Cu²⁺ ion over other metal ions with the same charge and close ionic radius. The relative standard deviations for six and twenty replicates with the same nanoparticles were found to be 1.7% and 2.1%, respectively.     

Thin Pd–23%Ag/stainless steel composite membranes: Long-term stability,life-time estimation and post-process characterisation

The long-term stability of Pd–23%Ag/stainless steel composite membranes has been examined in H₂/N₂ mixtures as a function of both temperature and feed pressure. During continuous operation, the membrane shows a good stability at 400 °C while the N₂ leakage increases very slowly at a temperature of 450 °C (P_feed = 10 bar). After 100 days of operation (P_feed = 5–20 bar, T = 350–450 °C), the N₂ permeance equals 7.0 × 10⁻⁹ mol m⁻² s⁻¹ Pa⁻¹, which indicates that the H₂/N₂ permselectivity still lies around 500, based on a H₂ permeance equal to 3.0 × 10⁻⁶ mol m⁻² s⁻¹ Pa⁻¹. Despite the generation of small pinholes, a membrane life-time of several (2–3) years (T ≤ 425 °C) is estimated for the experimental conditions employed based on long-term stability tests over 100 days. Post-process characterisation shows a considerable grain growth and micro-strain relaxation in the Pd–23%Ag membrane after the prolonged permeation experiment. Changes in surface area are relatively small. In addition, segregation of Ag to the membrane surfaces is observed. The formation of pinholes is identified as the main source for the increased N₂ leakage during testing at higher temperature.     

Azothia- and Azoxythiacrown Ethers as Ion Carriers. Part I. Cationic Response of Membrane Electrodes

13-Membered azothia- and azoxythiacrown ethers have been applied as ion carriers in ion-selective membrane electrodes. Their sensitivity and selectivity were studied towards alkali, alkaline earth, transition and heavy metal cations. It was found that membranes doped with the azoxythiacrown ether (A) show higher affinity towards Pb²⁺ than Cu²⁺ (log K_Cu,Pb ^pot = 1.7), whereas membranes with the azothiacrown ether (B) are more selective towards Cu²⁺ than Pb²⁺ (log K_Cu,Pb ^pot = -2.4). The discrimination of alkali and alkaline earth cations was found to be greater for B than for A. Electrodes with both ionophores suffered from strong interference by Ag⁺ and Hg²⁺. The relation between the carrier structure and electrode properties has been discussed.     

Adsorption of Cu2+ from aqueous solution onto iron oxide coated eggshell powder: Evaluation of equilibrium,isotherms, kinetics,and regeneration capacity

This study explored the adsorption behavior of Cu²⁺ onto iron oxide coated eggshell powder (IOESP) from aqueous solution. The effect of various operational parameters such as pH, contact time, initial adsorbate concentration, surfactant, and temperature on adsorption of Cu²⁺ ions was investigated using batch adsorption experiments. The optimum pH for Cu²⁺ adsorption was found to be 6.0. Kinetics of adsorption was found to follow the pseudo-second-order rate equation. The suitability of Langmuir and Freundlich adsorption models to the equilibrium data was investigated. The adsorption was well described by the Freundlich isotherm model indicating the presence of heterogeneous sites for Cu²⁺ adsorption. The adsorption of Cu²⁺ was increased in the presence of anionic surfactant (SDS) while cationic surfactant (CTAB) shows no significant change in adsorption capacity. Thermodynamic parameters showed that the adsorption of Cu²⁺ onto IOESP was feasible, spontaneous, and exothermic. Regeneration studies were performed using HCl, HCOOH, EDTA, and NaOH as eluting agent for Cu²⁺ desorption from saturated IOESP and the maximum regeneration was observed with HCl.