Low Adsorption Performance Research Articles

In-situ preparation of HPO42− intercalated NiFe layered double hydroxides for efficient U(VI) removal

The development of high-efficiency adsorption materials for efficient removal of U(VI) from nuclear wastewater has become a concern of environmental protection. LDHs, as adsorbent materials, lack functional groups, resulting in low adsorption performance. Herein, a novel and excellent radiation stable HPO42−-intercalated NiFe-LDH material (NiFe-LDH-P(x)) is synthesized by in-situ co-precipitation method. The effect of HPO42− content on the U(VI) performance of NiFe-LDH-P(x) is studied in detail. The results reveal that intercalation of HPO42− increases the interlayer spacing and specific surface area of NiFe-LDH, as well as the active sites between the interlayers. Therefore, NiFe-LDH-P(x) with moderate HPO42− content (10 %) can reach highest U(VI) adsorption capacity (350.88 mg·g−1). FTIR, SEM and XPS analyses educe that the efficient adsorption of uranium on NiFe-LDH-P(10 %) is mainly attributed to complexation, electrostatic attraction and ion exchange. In summary, NiFe-LDH-P(10 %) has great potential in removing uranium from wastewater, which provides a new idea for the synthesis of efficient adsorbents.

Predictive modeling for VOC adsorption on TiO2 filters: Implications for enhanced photocatalytic oxidation in indoor air quality management

Adsorption of volatile organic compounds (VOCs) onto the surface of a TiO2 filter is essential for initiating photocatalytic oxidation (PCO). This study investigated the adsorption coefficients (K) of 14 VOCs under different relative humidities (RH) and explored the influence of different air velocities on the adsorption of Methyl isobutyl ketone (MIBK). Consequently, a polyparameter linear free energy relationship (pp-LFER) model was established to predict lnK at 35 % RH (lnK35%). Moreover, the study found that lnK has a linear relationship with RH, represented as lnK=αRH+β. The parameters ′α′ and ′β′ can be accurately predicted using the Henry’s Law constant (K°OH) and lnK35%, respectively. By combining the pp-LFER model with regression equations for ′α′ and ′β′, it is possible to predict lnK for VOCs across various RH levels. The study also revealed that the adsorption coefficient of increases with escalating air velocities (0.04 – 0.34 m/s), primarily due to mass transfer. The observed low adsorption performance for aldehydes, commonly seen as by-products in the PCO process, suggests cautious usage of the PCO filtration system in practice before the by-products are eliminated downstream. This study offers valuable insights for the practical application of PCO technologies in the comprehensive removal of indoor VOCs.

Diatomite-Trichoderma viride composite microspheres for selective removal of anionic dyes and copper ions

Taking into account that Trichoderma viride dispersion mycelium existed many shortcomings, such as difficult to separate, easy to deactivate, and low adsorption performance, Diatomite-Trichoderma viride (DE-T. viride) composite microspheres were designed and prepared by chemical bonding, and anion dye and copper ion synergistic removal strategies were proposed. The adsorption performance of the composite microspheres on CR and Cu2+ were demonstrated by Zeta potential and Fourier infrared spectroscopy. The adsorption process followed the pseudo-second-order model, involving various mechanisms such as metal chelation, polysaccharide adhesion, hydrogen bonding, and electrostatic interactions. Intraparticle diffusion model identity that adsorption is controlled by multiple steps. Adsorption isotherms of CR and Cu2+ displayed excellent agreement with the Langmuir, Freundlich, and Temkin models. Impressively, DE-T. viride spheres exhibited maximum adsorption capacities of 176.3 and 63.8 mg/g for CR and Cu2+. Moreover, they displayed selective adsorption for anionic dyes, with capacities 8 and 10 times higher than those for cationic and neutral ionic dyes, respectively. T. viride microspheres generates extracellular polymers, which are rich in a variety of functional groups and can adsorb metal ions through chelation and transport, moreover, it adsorbs anions with positive charge. It is worth mentioning that DE-T. viride spheres exhibited ease of separation, stability, and reproducibility even after multiple adsorption-recycling cycles, maintaining an impressive adsorption rate of 80 %. In conclusion, these multifunctional, efficient, and eco-friendly DE-T. viride spheres present promising potential for environmental remediation, particularly in removing contaminants from various environmental matrices. Their outstanding performance, selectivity, and recyclability make them a valuable and sustainable solution for addressing pollution issues and promoting environmental sustainability.

Selective separation of target glycoproteins using boronate affinity imprinted copolymers: Precise identification and increase the number of recognition sites

The recognizing sites numbers and selectivity limitation of the sorbents itself is the main reason for the difficulty in increasing the target glycoproteins adsorption amount in the separation system.In this work, a new kind of porous block imprinted copolymers (BA-MF-CD-BA) with abundant boronic acid recognizing sites were firstly fabricated facilely synthesized through a in situ cross-linking copolymerization and host–guest interaction for specific separation of ovalbumin (OVA). The single boronate affinity recognizing sites are relatively difficult for selective capture glycoproteins of low concentration. This is because of that the single imprinted recognizing sites are generally related to the low adsorption performance and weak affinity. For solve these limitations, the high-density boronic acid recognizing sites were considered to grafted on the surface of sorbents. Firstly, the functional monomer 4-vinylphenylboronic acid (4-VBA) were used to prepare the matrix of boronate affinity copolymers with β-cyclodextrins (CDs). Subsequently, the CDs as a a linker to graft boronate affinity imprinted recognizing sites based adamantane (Ad) inclusion derivative, which can effectively increase the numbers of boronic acid recognizing sites. Owing to the abundant boronic acid recognizing sites synergistic binding, the as-prepared BA-MF-CD-BA exhibited high adsorption capacity towards OVA, which are approximately 3.5 orders higher than the affinity of single boronate affinity sorbents. Combining these excellent properties, BA-MF-CD-BA exhibit fast adsorption kinetics (30 min) and large adsorption capacities (129.12 mg g−1, pH = 8.0) at 298 K, and the existence of an evenly chemisorption monolayer is confirmed. Moreover, the high recyclability (after 8 cycles, 6.24% loss) demonstrated the BA-MF-CD-BAs’ practical application potential. In addition, BA-MF-CD-BA exhibited excellent selective adsorption performance of OVA from complex practical samples. This is because of that the high-density boronate affinity imprinted recognizing sites and the nanoporous structure of the imprinted copolymers matrix. Consequently, the high density boronate affinity imprinted copolymer can be an attractive option for selective enriching glycoproteins from practical samples.

Enhanced Hg(II) efficient and selective removal by post-functional Ti-MOF with 2，5 thiophene dicarboxylic acid

Toxic mercury ions in wastewater from industrial activities can wreak havoc on the natural environment and ecosystems. Adsorption treatment has been proved to be an effective measure to reduce mercury load in wastewater, but conventional adsorbents have lower adsorption performance. In this study, titanium-metal organic framework (Ti-MOF) was synthesized by solvothermal method, and then further modified by 2,5-thiophene dicarboxylic acid. In order to explore the morphology of the resulting material (OB-MIL-125 (Ti)) and the differences before and after modification, different characterization instruments have been employed. Meanwhile, the properties of materials at different pH were explored, and the adsorption capacity was deeply studied through thermodynamics, kinetics, and adsorption isotherms. The surface of OB-MIL-125 (Ti) had a rich pore structure, so the specific surface area is large, reaching 328.7 m2/g. At room temperature and pH= 5, the maximum removal rate of a 100 ppm solution reached 93.66%. The actual measured maximum adsorption capacity was 1435.98 mg/g. According to isotherm, kinetic and thermodynamic analysis, the process of removing Hg2+ was a multi-layer heterogeneous process, relying on chemical action for adsorption, and it was also a spontaneous exothermic process. The adsorbent presented excellent affinity for mercury and good regeneration ability. To sum up, the OB-MIL-125 (Ti) has great potential for remediation mercury-containing wastewater.

Review of Inexpensive Adsorbents for Removing Boron from Aqueous Solutions

Boron is one of the essential elements for plants, animals, and humans, but its excess poses a great risk to life. Therefore, it is necessary to effectively remove boron from various boron-containing aqueous solutions to reduce damage to living things. There have been many studies on the adsorbent for removing boron from the boron-containing aqueous solution, but many of them are expensive or cannot be industrialized or commercialized, so they remain in the laboratory stage. Reducing the cost of adsorbent and realizing commercialization can be said to be the key links to successfully solving the problem of boron removal from an aqueous solution. The purpose of this review is to conduct a comprehensive analysis of inexpensive adsorbents used for boron removal from industrial wastewater and drinking water and to discuss future research directions. This article summarizes the development and utilization of inexpensive adsorbents, including inorganic materials, natural materials, and wastes. The limitations of performance, applicable conditions, sources, et al., of inexpensive adsorbents currently developed and utilized were analyzed, and future research directions were discussed. Most inexpensive adsorbents have a limited range of use, and compared to organic materials, inorganic materials have very low adsorption performance. The development of adsorbents using natural materials or waste is not active. Therefore, further research is needed to improve the performance of inorganic adsorbents, develop environmentally sustainable and efficient adsorbents, and recycle adsorbents.

Density functional theory study on direct dehydrogenation of propane catalyzed by N-, O-, and P-doped graphene catalysts

The density functional theory was used to calculate the reaction mechanism and selectivity of nonmetallic single-atom catalysts, such as N, O, and P, doped on graphene in the direct dehydrogenation of propane (PDH) . Our results show that the rate-controlling step in PDH varies with the doping atom. We also found that N, O, and P nonmetallic single-atom-doped graphene catalysts showed relatively low adsorption performance for propane and the active site was the C atom adjacent to N, O, and P, rather than the doped atom itself. Interestingly, for the O-doped graphene catalysts, which can reduce the reaction energy barrier by searching for multiple transition states, and the more transition states in the reaction path, the lower the energy barrier for the reaction rate-controlling step. Finally, the results show that the energy barrier of P-doped propane direct dehydrogenation reflecting the speed control step is the lowest, which is 44.32 kcal·mol−1, and the energy barrier of deep dehydrogenation is 53.08 kcal·mol−1; so it has good selectivity. Therefore, the P-doped graphene catalyst has a promising application as a nonmetallic catalyst for the direct PDH, which provides the possibility for the design of cheap and environmentally friendly catalysts.

Poisoning mechanism of the coexistence K and SO2 on the deNOx of MnO2/TiO2 catalyst at low temperature

Manganese-based catalysts supported by TiO2 (MnO2/TiO2) show good deNOx performance at low temperature. However, the microscopic impact mechanism of poisonous substances such as K and SO2 on the deNOx of the MnO2/TiO2 catalyst is a grey area. In this work, the poisoning mechanism of K and SO2 coexistence on the deNOx of the MnO2/TiO2 catalyst was explored by using a density functional theory combined with experimental methods. SO2 has low adsorption performance on the MnO2/TiO2 (001) surface, while it can be oxidized to form SO3, and it will react with the catalyst to form sulfates. K poisoning makes NH3 and NO molecules more difficult to be adsorbed on the MnO2/TiO2 (001) surface. However, when SO2 is introduced on the catalyst surface with K poisoning, it can interact with K and change the charge transfer from K to the catalyst surface, alleviating the K poisoning of the catalyst. These results contribute to the understanding of the mechanism of K and SO2 co-poisoning on the deNOx of Mn-based catalysts at a microscopic level, and provide guidance for designing Mn-based catalysts with high anti-poisoning ability.

A facile pyrolysis synthesis of Ni doped Ce2O3@CeO2/CN composites for adsorption removal of Congo red: Activation of carbon nitride structure

Sheet-like Ni doped Ce2O3@CeO2/CN composite is synthesized by tuning the introduction of nickel in a facile and low-cost pyrolysis process. Due to the activation of the shell-core Ce2O3@CeO2 structure, the nitrogen chemical state in the carbon nitrides is mainly in the form of an N-(C3) structure, inducing the production of excellent electronic conductivity and positive charges on carbon nitrides. For the pyrolytic synthesis of the composite, the amount of nickel doping is a crucial factor. Under no nickel condition, only CeO2 is synthesized and positively charged. With increasing nickel content, Ni doped CeO2/CN composite is prepared and negatively charged due to its main component of CeO2 and the change of its carbon nitride structure. Ni doped CeO2 prepared with high enough nickel content presents individual NiO particles and its negatively charged surface. The removal of these designed composites for anionic Congo red is utilized to reveal the significant influence of their surface structure. Ni doped Ce2O3@CeO2/CN composite depicts the highest removal performance. Ni doped CeO2/CN composite, despite the great change in its carbon nitride structure, still has much higher removal efficiency than pure CeO2. However, Ni doped CeO2 is found to have lower adsorption performance than pure CeO2.

Mechanisms and novel performance of ZrO2/Fe3O4 composite for phosphate recovery from wastewater

In this study, a composite material of Fe3O4 with excellent physical adsorption and ZrO2 with excellent chemical adsorption properties was synthesized to maximize the phosphate recovery efficiency in water. Fe3O4, ZrO2, and Fe3O4/ZrO2 were prepared using co-precipitation and characterized using various surface and structural analysis techniques. Fe3O4 exhibited both physical and chemical adsorption mechanisms, as evidenced by its pseudo-first- and pseudo-second-order kinetics during the adsorption/desorption process, while the dominant adsorption mechanism for ZrO2 was chemical adsorption. The adsorption mechanism of Fe3O4/ZrO2 shows physical adsorption by electrostatic attraction followed by chemical adsorption in which potential bidentate inter-complex and monodentate are formed. From the hydroxyl group analysis, it can be seen that the hydroxyl radicals increased by about 3.5 times or more due to the presence of Fe3O4 on the surface of ZrO2. Overall, the synthesis of Fe3O4/ZrO2 successfully improved the low adsorption performance of Fe3O4 while ameliorating the disadvantages of ZrO2.

The carrier effect mechanism of butachlor in water by three typical microplastics.

Butachlor (BUT) is a widely used herbicide that can cause environmental problems when used excessively. BUT has been found to exist in large quantities in the water environment so far. As an agricultural pre-emergent herbicide, BUT can enter the water environment through multiple channels and cause pollution. This study investigated the mechanism of three types of microplastics (MPs): polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC) to remove BUT from water. The adsorption behavior between MPs and BUT under different factors, namely pH, salt ion concentration, and aging, was investigated. This study further investigated the desorption and aging of BUT-adsorbed MPs. In this research, the adsorption capacity of BUT by PE, PP, and PVC are 13.65 μg/g, 14.82 μg/g, and 18.88 μg/g, respectively, and the order of carrier effect was: PVC>PP>PE. Experiments show that MPs have low adsorption performance on the microgram level for BUT. The adsorption behavior of PE, PP, and PVC on BUT conformed to pseudo-second-order kinetics, indicating the presence of physical and chemical adsorption. The Langmuir isotherm model fits well, indicating that the adsorption is a single-layer adsorption process. The pH value causes slight fluctuations in the overall carrier effect. Low concentration of salt ions can inhibit the carrier effect, and high concentration will promote the interaction between MPs and BUT. Aging experiments show that the carrier effect of the original materials was higher than the adsorption capacity of hydrogen peroxide and MPs after acid aging, and acid aging can cause the adsorption capacity to drop significantly.

A green 3-step combined modification for the preparation of biomass sorbent from waste chestnut thorns shell to efficient removal of methylene blue

Although several green methods for the preparation of biomass adsorbents have been proposed, the low adsorption performance of the biomass adsorbents prepared by these methods has limited the development of this technological route. This is the first work that uses an ultrasound-assisted binary solvent system and low temperature ice crystal fixation to achieve high adsorption performance of a biomass sorbent. Chestnut thorns shell (CTS) sorbent with high adsorption performance on MB was successfully prepared with an adsorption performance of 305.81 mg/g, which is on par with most high temperature carbonized adsorbents. Further reaction kinetics, TEM, XPS and FTIR studies showed that the MB adsorption of CTS was through electrostatic attraction, hydrogen bonding, ion–dipole interaction and π-π interaction. After five cycles, the adsorption capacity of the adsorbent remained at a high level. This work provided an effective strategy for safer and greener preparation of high adsorption performance adsorbents from agroforestry waste.

Biomass porous carbon as the active site to enhance photodegradation of oxytetracycline on mesoporous g-C3N4.

Graphitic carbon nitride (g-C3N4) is widely used in photocatalytic adsorption and degradation of pollutants, but there are still some problems such as low adsorption performance and high electron–hole recombination efficiency. Herein, we propose a new molten salt assisted thermal polycondensation strategy to synthesize biomass porous carbon (BPC) loaded on g-C3N4 composites (designated as BPC/g-C3N4) with a hollow tubular structure, which had a high surface area and low electron–hole recombination rate. The study shows that the morphology of g-C3N4 changes dramatically from massive to hollow tubular by molten salt assisted thermal polycondensation, which provides a base for the loading of BPC, to construct a highly effective composite photocatalyst. BPC loaded on g-C3N4 could be used as the active site to enhance Oxytetracycline (OTC) removal efficiency by adsorption and with higher electron–hole separation efficiency. As a result, the BPC(5%)/g-C3N4 sample presented the highest photocatalytic degradation efficiency (84%) for OTC degradation under visible light irradiation. The adsorption capacity and photocatalytic reaction rate were 3.67 and 5.63 times higher than that of the g-C3N4, respectively. This work provided a new insight for the design of novel composite photocatalysts with high adsorption and photocatalytic performance for the removal of antibiotic pollutants from wastewater.

Facile modification of graphene oxide and its application for the aqueous uranyl ion sequestration: Insights on the mechanism

Graphene oxide (GO) has been proved with favorable affinity to U(VI), while some drawbacks such as poor dispersity and low adsorption performance limit its application. Herein, cetyltrimethylammonium bromide (CTAB) modified graphene oxide (MGO) composites were successfully fabricated, characterized and compared with graphene oxide (GO) in the sequestration of U(VI) in aqueous solutions. The results showed that maximum adsorption rate of MGO (99.21%) was obviously higher than that of GO (66.51%) under the same initial condition. Simultaneous introduction of C–H and NO coupled with the enhanced dispersity of GO after modification were mainly responsible for the updated performance verified with multiple characterization techniques. Based on the results of kinetics and isotherms investigations, the experimental data were best described by Pseudo-first-order kinetic model and Redlich-Peterson isotherm model. The results of ΔH, ΔS and ΔG show that adsorptive behaviors of uranyl ion on MGO are endothermic and spontaneous. The study provides a feasible alternative to the chemical modification of GO and enhancing the performance towards uranyl ion removal from solution.

Preparation of ionic liquids functionalized nanodiamonds-based composites through the Michael addition reaction for efficient removal of environmental pollutants

Nanodiamonds (ND) is a novel type of carbon nanomaterials with small size, large specific surface areas, low cost and some other physicochemical properties. However, the environmental applications of ND are still rarely reported because of its low adsorption performance. In this work, we reported for the first time for the surface modification of ND with ionic liquids through a facile and effective Michael addition reaction. To synthesis of the ternary ND@IL composites, ND was first linked with APTES by a silanization reaction and then [C16VIm+] [Br−] was conjugated on the surface of amino groups functionalized ND via the Michael addition reaction. The ND@IL composites were applied as adsorbents for removal of Congo red (CR) from aqueous solution and displayed high removal efficiency (92.78%) at room temperature and neutral solution. Under certain adsorption conditions, the adsorption capacities of pristine ND and ND@IL towards CR is 61.1 and 226.4 mg g−1, respectively. The pseudo-second-order model fitting the adsorption kinetic data is superior to pseudo-first-order model and Freundlich isotherm model describes the experimental data well. Further experiments showed that the removal process was pH dependence, exothermic and spontaneous. More importantly, ND@IL composites could be regenerated via adjustment of pH values and still maintain high adsorption capacity after five regeneration cycles. All of the above results demonstrated that these ionic liquids modified ND are promising adsorbents for highly efficient and quick removal of environmental pollutants from aqueous effluents.

Covalent organic frameworks as efficient adsorbent for sulfamerazine removal from aqueous solution

Here, TPB (triphenylbenzene) – DMTP (dimethoxyterephthaldehyde) -COF was prepared, characterized and used as effective adsorbent for the removal of sulfamerazine (SMT) from aqueous solution. Its adsorption characteristics and mechanism were explored. With large channel (∼3.3 nm), high specific surface area (2115 m2/g), and high crystallite, TPB-DMTP-COF showed high adsorption capacity (209 mg/g), fast adsorption equilibrium (80 min), and good reusability. Natural pH condition was optimal for its adsorption capacity, while electrostatic repulsion between TPB-DMTP-COF and SMT accounted for the low adsorption performance at acidic or alkaline conditions. According to the DFT method, SMT molecules adsorbed in the pore-sites of COFs via C–H···π interaction was the predominant and stable adsorption configuration accounting for the efficient removal of SMT in large quantity. This study revealed the great adsorption potential of COFs skeleton itself in the application of environmental remediation.

CO2 geological sequestration: Displacement behavior of shale gas methane by carbon dioxide injection

Carbon dioxide (CO2) sequestration in deep shale reservoirs with enhanced shale gas methane (CH4) recovery contributes to both CH4 recovery and CO2 emission mitigation. In this work, the adsorption behaviors of pure CH4 and CO2 on shales, and the displacement behaviors of CH4 adsorbed on shales by CO2 injection were investigated. The single component adsorption indicates that the simplified Ono-Kondo lattice model can well describe both CH4 and CO2 adsorption on shales. The maximum adsorption capacity of CH4 obtained from the simplified Ono-Kondo lattice model shows significant linear correlation with the micropore parameters of shales, while this linear correlation is weak for CO2. The investigation on the displacement behaviors based on the improved experimental procedure and data processing method raised in this work confirms that CH4 adsorbed on shales can be displaced by CO2, which provides the experimental evidence for the feasibility of CO2 sequestration in shale reservoirs with enhanced CH4 recovery. The amounts of recovered CH4 and stored CO2 increase with CO2 injection pressure. The recovery yield of CH4 due to CO2 injection is higher for shales with smaller micropore parameters or lower adsorption performance. The microscopic mechanism of the displacement process is strongly related to the injection pressure of CO2. Based on the conceptual model established for the process of CH4 adsorbed on shales displaced by CO2 injection, it is recommended to inject CO2 after partial desorption of CH4, which can improve CH4 recovery and CO2 sequestration of the target shale reservoirs.

Zeolitic tuffs for acid mine drainage (AMD) treatment in Ecuador: breakthrough curves for Mn2+, Cd2+, Cr3+, Zn2+, and Al3.

Zeolitic tuff constitutes a technical and economical feasible alternative to manage acidic waters in initial phases of generation. A study of cation exchange with two zeolitic tuffs from Ecuador and one from Cuba has been conducted using breakthrough curve methodology. Cations Mn2+, Cd2+, Cr3+, Zn2+, and Al3+ have been chosen owing to their presence in underground water in exploration activities (decline development) in Fruta del Norte (Ecuador). Zeolites characterized by X-ray diffraction and thermal stability after heating overnight as heulandites show a similar exchange behavior for the five cations studied. The clinoptilolite sample Tasajeras shows a relevant cation exchange performance expressed in the important increment of spatial time to reach the breakthrough point in comparison with heulandite samples. The maximum length of unused beds was found for Cr3+ and Zn2+ cations showing, therefore, a lower adsorption performance in relation with Mn2+ and Cd2+. A final disposal method of metal-loaded zeolites with cement is proposed.

The role of oxygen functional groups in the adsorption of heteroaromatic nitrogen compounds

A wood-based activated carbon (AC) was oxidized using different oxidants. The resultant adsorbents were applied to adsorb nitrogen (N) containing compounds that appeared in light cycled oil. Appropriate oxidation treatment can increase oxygen functional groups on the surface of AC without much damage to its pore structure. Oxygen functional groups play a key role in enhancing adsorptive selectivity of carbons. Lactone groups can facilitate the selective removal of 1-ring N compounds. Phenolic groups, total CO2-releasing groups and total O groups show an improvement in the adsorption of 2-ring N compounds. Aldehyde groups favor the adsorption of 3-ring and 4-ring N compounds. However, excessive oxidation can result in the collapse of pore structure and closure of pore channels. For instance, the carbon oxidized by a mixture of concentrated H2SO4 and HNO3 has an extremely low adsorption performance.

In situ detection and removal of metal ion by porous gold electrode

A sensing electrode for the detection of heavy metal ions in aqueous solution selectively measured the concentrations of target materials on its functionalized surface, which has affinity to target metal ions. Target ions were adsorbed simultaneously on the functionalized electrode during the sensing process. Therefore, to understand this, experiments on the amperometric response and isotherms with an initial concentration of Hg 2+ were tested. Detection current was dependent on the concentration of Hg 2+, and the equilibrium concentration of Hg 2+ adsorbed to the electrode showed a Langmuirian shape. Correlation between the detection current and removal capacity for Hg 2+ revealed that it is possible to estimate the adsorbed concentration on the electrode during the sensing step. Although the macroporous gold electrode prepared herein showed relatively low adsorption performance compared to conventional adsorbents, when we prepare nanoporous gold electrodes with a uniform nanopore structure and large surface area, in situ detection and simultaneously removal of metal ions by nanoporous gold electrode will be possible.