Anions In Wastewater Research Articles

Impacts of chloride ions on the electrochemical decomplexation and degradation of Cr(III)-EDTA: Reaction mechanisms of HO• and RCS

The removal of Cr(III)-organic complexes, encompassing both decomplexation and ligand degradation, presents significant challenges in industrial wastewater treatment. As one of the most common anions in wastewater, Cl− significantly improves the efficiency of electrochemically removing Cr(III)-organic complexes through generated reactive chlorine species (RCS). In the electrochemical chlorine (EC/Cl2) process, extensive experimentation revealed that ClO• plays a dominant role in the degradation of Cr(III)-EDTA, surpassing the effects of free chlorine, direct electrooxidation, HO•, and other RCS. Density functional theory calculations indicated that RCS, primarily Cl• and ClO•, preferentially oxidize the ligand in Cr(III)-EDTA via H-abstraction, whereas HO• trends to attack the Cr atom through electron transfer. The influential factors on the degradation efficiency of Cr(III)-EDTA, Cr(VI) yield, and total organic carbon removal in EC/Cl2 were also assessed, including Cl− concentration, current density, and pH. Real industrial wastewater was employed as a reaction matrix to evaluate the application of the EC/Cl2 process for treating Cr(III)-EDTA, accompanied by energy efficiency calculations. Additionally, a two-chamber reactor was established to simultaneously oxidize Cr(III)-EDTA at the anode and reduce Cr(VI) at the cathode. This study provided insight into developing RCS-dominated AOPs to effectively decomplex and decompose organic Cr(III)-complexes in Cl−-containing industrial wastewater.

One-pot fabrication of nanoscale zero-valent iron scaffolded onto graphitic carbon nitride as bifunctional nanohybrid in sequestering U(VI) and Cr(VI) with boost performance and intrinsic mechanism

In this paper, we reported an innovative one-pot fabrication approach of a bifunctional nanohybrid through scaffolding of nanoscale zero-valent iron onto the inter-layer structure of graphitic carbon nitride in sequestering U(VI) and Cr(VI) in wastewater. The microstructures, morphologies and chemical compositions of the as–fabricated g-C3N4/NZVI nanohybrid before and after U(VI)/Cr(VI) sequestration were exploited in detail by applying various physicochemical and spectroscopic methods. Batch experimental results demonstrated that sequestration of targeted U(VI)/Cr(VI) by g-C3N4/NZVI was higher than those of pure NZVI or g-C3N4 due to the pronounced boost performance, which was ascribed from the introduction of g-C3N4 as matrix inhibited the oxidation of NZVI and improved its reactivity. The pH effect was also elucidated and it was found that lower pH facilitated the sequestration of the negatively–charged Cr(VI), while higher pH benefited the sequestration of the positively–charged U(VI). Moreover, the characterization insights into intrinsic mechanism manifested that sequestration of U(VI)/Cr(VI) was fulfilled through a synergistic effect of adsorption, reduction and coprecipitation. This work is of great significance for understanding the combined sequestration mechanism of U(VI) and Cr(VI), and usage of g-C3N4/NZVI in sequestration of severe dangerous metal ions, especially efficient detoxification of toxic cations and anions in wastewater.

Self-templating synthesis of biomass-based porous carbon nanotubes for energy storage and catalytic degradation applications

Dwindling energy sources and a worsening environment are huge global problems, and biomass wastes are an under-exploited source of material for both energy and material generation. Herein, self-template decoction dregs of Ganoderma lucidum-derived porous carbon nanotubes (ST-DDLGCs) were synthesized via a facile and scalable strategy in response to these challenges. ST-DDLGCs exhibited a large surface area (1731.51 m2 g−1) and high pore volume (0.76 cm3 g−1), due to the interlacing tubular structures of precursors and extra-hierarchical porous structures on tube walls. In the ST-DDLGC/PMS system, the degradation efficiency of capecitabine (CAP) reached ∼97.3% within 120 min. Moreover, ST-DDLGCs displayed high catalytic activity over a wide pH range of 3–9, and strong anti-interference to these typical and ubiquitous anions in wastewater and natural water bodies (i.e., H2PO4−, NO3−, Cl− and HCO3−), in which a 1O2-dominated oxidation was identified and non-radical mechanisms were deduced. Additionally, ST-DDLGC-based coin-type symmetrical supercapacitors exhibited outstanding electrochemical performance, with specific capacitances of up to 328.1 F g−1 at 0.5 A g−1, and cycling stability of up to 98.6% after 10,000 cycles at a current density of 2 A g−1. The superior properties of ST-DDLGCs could be attributed to the unique porous tubular structure, which facilitated mass transfer and presented numerous active sites. The results highlight ST-DDLGCs as a potential candidate for constructing inexpensive and advanced environmentally functional materials and energy storage devices.

Modified fly ash as an effect adsorbent for simultaneous removal of heavy metal cations and anions in wastewater

A novel fly ash-based composite material with multiple adsorption sites was synthesized to remove Pb2+, Cd2+ and AsO33− from wastewater. In a single pollutant system, when pH = 6, the initial pollutant concentration was 100 mg/L, and the dosage was 4 g/L, the removal rates of Pb2+, Cd2+ and AsO33− by modified DTCH-MFA were increased by 54.4 %, 2.14 % and 6.44 % compared with the unmodified FA. For DTCH-MFA, the maximum adsorption capacities of Pb2+, Cd2+ and AsO33− were 15.86 mg/g, 3.74 mg/g and 5.63 mg/g, which increased by 14.04 mg/g, 0.28 mg/g and 1.87 mg/g than FA. In the actual wastewater system, DTCH-MFA could simultaneously remove Pb2+, Cd2+ and AsO33− with removal rates of 85.31 %, 95.98 % and 47.57 %. The relevant adsorption mechanisms were studied via XRD, FTIR, VSM and XPS, which revealed electrostatic interaction, and chelation reaction played important roles to the efficient adsorption. Besides, the adsorption processes were consistent with the Pseudo-second-order Kinetics and Freundlich isothermal model. DTCH-MFA could simultaneously adsorb Pb2+, Cd2+ and AsO33− within 2–8 h, which extended the related studies on the removal of heavy metal cations and anions by FA-based adsorbents.

Comprehensive effect of water matrix on catalytic ozonation of chloride contained saline wastewater

Chloride ion (Cl−) is one of the most common anions in wastewater and saline wastewater, but its elusive effects on organics degradation are not clear yet in many cases. In this paper, the effect of Cl− on organic compounds degradation is intensively studied in catalytic ozonation of different water matrix. It was found that the effect of Cl− is almost completely reflected by transforming ·OH to reactive chlorine species (RCS), which is simultaneously competitive with organics degradation. The competition between organics and Cl− for ·OH directly determines the ratio of their consumption rate of ·OH, which depends on their concentration and reactivity with ·OH. Especially, the concentration of organics and solution pH may change greatly during organics degradation process, which will correspondingly influence the transformation rate of ·OH to RCS. Therefore, the effect of Cl− on organics degradation is not immutable, and may dynamically change. As the reaction product between Cl− and ·OH, RCS was also expected to affect the degradation of organics. But we found that Cl· had no significant contribution to the degradation of organics in catalytic ozonation, which may due to its reaction with ozone. Catalytic ozonation of a series of benzoic acid (BA) with different substituents in chloride contained wastewater was also investigated, and the results showed that the electron-donating substituents can weaken the inhibition of Cl− on BAs degradation, because they increase the reactivity of organics with ·OH, O3 and RCS.

Adsorptive removal of anionic azo dye by Al3+-modified magnetic biochar obtained from low pyrolysis temperatures of chitosan.

Magnetic γ-Fe2O3/Al3+@chitosan-derived biochar (m-Fe2O3/Al3+@CB) was prepared by introducing magnetic maghemite (γ-Fe2O3) nanoparticles and aluminum sulfate [Al2(SO4)3] into chitosan-derived biochar (CB) obtained at low pyrolysis temperatures. m-Fe2O3/Al3+@CB was used to remove typical anionic azo dye (Congo red, CR). Effects of initial CR concentration, contact time, initial pH value, background electrolytes, and temperature on CR adsorption by m-Fe2O3/Al3+@CB were studied. Compared with magnetic chitosan-derived biochar (m-Fe2O3@CB), m-Fe2O3/Al3+@CB exhibited excellent performance for a wider range of pH values (pH 1-7) and in the presence of background electrolyte. The introduction of Al3+ is an effective method for improving the properties of magnetic chitosan-derived biochar. High CR adsorption capacity (636.94mgg-1) of m-Fe2O3/Al3+@CB could result from collaborative effect of flocculation/coagulation and electrostatic attraction. These results demonstrated that m-Fe2O3/Al3+@CB is a potential adsorbent for effective removal of organic dyes from aqueous solution due to its high adsorption capacity and convenient magnetic recovery and stronger anti-interference ability against coexisting anions in wastewater.

Magnetic biochar based on platanus leaves and iron sludge for persulfate activation and catalytic degradation of tetracycline

In this study, a novel magnetic biochar (BC-Fen), synthesized by one-step pyrolysis at 800 °C using platanus leaves and iron-containing sludge in different mass ratios, was used to activate persulfate (PS) for tetracycline (TC) degradation. Results show that BC-Fe1:2 exhibited excellent degradation performance (91.4%), much better than the raw biochar (BC) (77.1%). And electron paramagnetic resonance (EPR) techniques demonstrated radical (SO4·−, ·OH, O2·−) and non-radical (1O2) pathways in BC-Fe1:2/PS, S O4·− was further proved to be the main active species by quenching experiments. Liquid chromatography-mass spectrometry (LC-MS) was utilized to identify the intermediates of TC and three possible degradation pathways were proposed. Additionally, the BC-Fe1:2 was weakly affected by pH and the coexisting anions in wastewater, and could still remove 80% of TC in the third cycle experiment. This study provides a new idea for converting backwash iron-containing sludge from groundwater treatment plants into valuable catalysts, and provides new insights into the key role of low-cost magnetic biochar in PS activation.

A Novel Conjugate Mechanism for Enhancing the Adsorption Capacity of Amine-Functionalized Activated Rice Husk Ash for Simultaneous Removal of Organics and Anions in Wastewater: Experimental and Theoretical Explanations.

In this study, amine-functionalized rice husk ash (TRI-ARHA) was prepared and successfully applied as a multipurpose adsorbent for simultaneous removal of organics (i.e., methyl orange, MO), nitrate, and phosphate in wastewater with adsorption capacities of around 16.6 mgMO/g, 32.9 mgNO3–-N/g, and 13.4 mgPO43–-P/g. These capacities were superior to those of the other commercially available materials such as activated carbon and ion-exchange resins in both individual and multipollutant adsorption experiments. In addition, the simultaneous adsorption of three components gives a higher adsorption capacity than individual adsorption for each anion (e.g., 1.18 times for nitrate and 1.11 times for phosphate). A conjugated adsorption mechanism may occur on the surface of the TRI-ARHA material, which can be ascribed to the amine groups in the MO molecule that are further activated by H+ (released from the surface amine groups) or Na+ ions (present in the solution), to form new adsorption centers for nitrate and phosphate. The integration process of H+ and Na+ to the nitrogen positions of MO was also studied by computational chemistry with the basis set of B3LYP/6-32G* calculated by Gaussian 16 software. The application in the treatment of real wastewaters proved that the TRI-ARHA material was more advantageous for multipollutant removal than other materials, thanks to its conjugated adsorption mechanism.

Renewable molybdate complexes encapsulated in anion exchange resin for selective and durable removal of phosphate

The existence of many anions in wastewater reduces the removal efficiency of phosphate by adsorbents under realistic conditions. Facing this challenge, the study reports on an insistent and stable composite adsorbent of molybdate complexes Fe-(MoOx) embedded in a macroporous anion exchange resin (D-201). [Fe(MoOx)]-D-201 shows 93.7% adsorption capacity (28.3 mg/g) for phosphate even when the molar concentration of coexisting ions is 5 times higher than phosphate. The capacity of adsorbent is maintained more than 84.2% after five regeneration cycles to remove phosphate in the wastewater containing coexisting ions. The ability of highly selective removal of phosphate is maintained during the regeneration cycles explained by the change of the binding of molybdate clusters with phosphate, which is due to the different structures of molybdate clusters depending on various pH. In general, this work puts forward a new idea for the development of phosphorus removal adsorbents for the treatment of wastewater containing coexisting ions.

Assessment of nitrate, phosphate and sulphate levels in wastewater from Muhammad Ayuba dam in Kazaure, Jigawa state, Nigeria

In the continuation of the evaluation of the physicochemical parameters of wastewater of Muhammad Ayuba dam in Kazaure, Nigeria, this investigation was carried out for the assessment of certain nutrients parameters i.e., nitrate, phosphate and sulphate that are primarily responsible for the eutrophication. This investigation was conducted during November, 2019 to January, 2020 (Harmattan season) to measure the content of nitrate, phosphate and sulphate ions in the wastewater collected from Muhammad Ayuba dam. During the study, standard techniques were used to determine the content of nitrate, phosphate and sulphate using spectrophotometer at specific wavelengths in determination of parameter of interests. The results obtained indicated that the concentrations were in the range of 78.50 – 88.40 mg/L for nitrate, 55.70 – 62.40 mg/L for phosphate and 91.40 – 100.20 mg/L for sulphate ions, respectively. The contents of nitrate, phosphate and sulphate in the wastewater exceeded the limit set by FAO/WHO for these anions in wastewater with exception of sulphate ions that was below the limit. Pearson correlation (r = 0.484) of the different anions indicated that their level of contamination might be traced to the same source means runoff from fertilizer application. Therefore, the water of the dam is majorly polluted with domestic wastes and absolutely rich in sulphate ions especially detergents from nearby houses. The study also revealed gradual accumulation of anions in the wastewater of the dam suggested more pronounced pollution in it. Thus, regular monitoring of these ions must be required to evaluate their environmental impacts and possible potential risks.

Treatment of cyanide wastewater dynamic cycle test by three-dimensional electrode system and the reaction process analysis

ABSTRACT Dynamic three-dimensional electrode system treatment of cyanide wastewater used coal-based electrodes as cathode and anode, activated carbon as particle electrodes, the effects of applied voltage, reaction time and flow rate on ion removal rate were studied. SEM-EDS and XPS were used to study the morphology of coal-based electrode and the composition and existing state of the load substances, and the reaction mechanism were analysed and discussed. The results show that the removal rates of CNT, Cu, Zn, CN−, SCN− in cyanide wastewater were 97.03%, 95.79%, 99.82%, 99.42% and 94.19%, respectively, when the applied voltage of 4 V, the electrode distance of 10 mm, the flow rate of 30 ml/min, the reaction time of 2.5 h and the dosage of activated carbon particles of 2 g. The applied voltage is the key factor affecting ion removal. When the voltage was 2 V, the ion removal is mainly due to the synergistic effect of chemisorption and electrosorption. The CN−, SCN−, and metal cyanide complex anions in wastewater migrate to the anode of coal-based anode and particle electrode rapidly under the combined action of electric field and magnetic stirring. On the surface of porous coal-based electrode, the removal of CN−, SCN− was mainly attributed to the oxidation of oxygen evolution from the anode reaction, while the removal of Cu, Zn and other metal ions was mainly by the electrodeposition process on the cathode surface.

Efficient simultaneous removal of cadmium and arsenic in aqueous solution by titanium-modified ultrasonic biochar

Simultaneous removal of cations and anions in wastewater has always been a great concerned environmental problem. In this study, a friendly and inexpensive biosorbent to simultaneously remove Cd(II) and As(V) from aqueous solution was synthesized by ultrasonic biochar and nanoscale TiO2 (TD), and the obtained sorbent was named as BCTD. The maximum sorption capacities of Cd (72.62 mg/g) and As (118.06 mg/g) were much higher than that of other carbon-materials. Both experiments showed that the Cd(II) and As(V) adsorption capacity was above 70% at pH = 5. The Cd(II) and As(V) adsorption on BCTD had a competitive effect in binary metal solutions at above 100 mg/L. The BET, SEM-EDS, FTIR and XPS analyses proved that ultrasonically reacting enhanced the surface area and pore volume of biochar and TD was supported on the biochar surface and inner pores successfully, and the dominant sorption mechanism by BCTD was the ion exchange and complexation.

Comparative performance of green rusts generated in Fe0–electrocoagulation for Cd2+ removal from high salinity wastewater: Mechanisms and optimization

The treatment of wastewater containing high concentration of inorganic salts has always been one of the focuses of environmental researchers. In this work, the effect of Cl− and SO42− on the removal of Cd2+ from wastewater using Fe0-electrocoagulation (Fe0-EC) were investigated by evaluating the transformation of Fe mineral. The experimental results indicated that the removal of Cd2+ from wastewater was depended on the property of Fe minerals. The generation of sulfate green rust (GRSO4) produced in the presence of SO42− showed stronger adsorption than the chloride green rust (GRCl) for Cd2+, and GRSO4 was obtained even in the mixture Cl− and SO42− solutions, because Fe(II)–Fe(III) GRs (layered double hydroxides, LDHs) showed stronger affinity for divalent SO42− than monovalent Cl−. High concentration of inorganic anions in wastewater resulted in the negative charged Fe flocs. High concentration of Cl− promoted the oxidation of Fe(II) to Fe(III) by chlorine–containing oxidants, and increased the proportion of Fe(III)/Fe(II) in Fe flocs, secondary Fe mineral magnetite (Fe3O4) was formed because of the increase of pH. Therefore, the presence of GRSO4 intermediate increased the Cd2+ removal by adsorption (coagulation and coprecipitation), and then the generated GRSO4 were gradually transformed into lepidocrocite (γ–FeOOH) by oxygen from air. Finally, the parameter optimization were conducted by adjusting the ratio of Cl− and SO42− (RC:S), current density (j), initial pH (pHi), initial Cd2+ concentration (C0), and temperature (T0). The removal efficiency of Cd2+ reached 99.5% after 10 min Fe0-EC under the optimal parameters: RC:S = 25:50 mmoL/mmol, j = 6 mA/cm2, pHi = 7–9, and T0 = 40 °C.

A multi-dye containing MOF for the ratiometric detection and simultaneous removal of Cr2O72− in the presence of interfering ions

Among the heavy metals commonly found in wastewater, Cr2O72− is considered the most hazardous due to its high toxicity, carcinogenicity, and mutagenicity. Nevertheless, detection and removal of Cr2O72− remains a serious challenge as it competes with other metal cations and anions in wastewater. Herein, self-calibration of the emission intensities at two different wavelengths was introduced to microporous media to facilitate the ratiometric detection and simultaneous removal of Cr2O72− in the presence of excess interfering ions. Specifically, a multi-dye (7-amino-4-methylcoumarin and resorufin) containing metal-organic framework-801 (Dyes⊂MOF-801) was developed and tested for the detection and removal of Cr2O72− from wastewater. Dyes⊂MOF-801 exhibited accurate detection of Cr2O72− with high sensitivity in the presence of a 260-fold excess of potentially interfering ions. Its maximum removal capacity was 83 mg/g and was achieved within 3 min, even in the presence of excess metal ions and 10-fold excess concentrations of anions. In addition, the residual concentration of Cr2O72− was simultaneously checked using ratiometric detection of Dyes⊂MOF-801, so that the removal of Cr2O72− could be immediately confirmed.

Study on the influence of surface potential on the nitrate adsorption capacity of metal modified biochar.

Carbon materials, as effective adsorbents to numerous aqueous cationic contaminants, have been hardly applied to remove anions in wastewater. In this work, different modifying agents were used to modify corncob biochars (CC) and the surface potentials of these modified biochars were determined. Based on the findings, modification principle was determined to reveal the relationship between surface potentials of the biochars and their nitrate adsorption capacities. The surface potential was dominated by the metal cations and multivalent cations led to even positive zeta potential. The formation of metal oxide not only led to the augment in surface area but also increase the surface charge. FeCl3-modified biochar (Fe-CC) with the highest positive surface charge was utilized to remove anions (nitrate) from aqueous solutions. Characterization results confirm that Fe2O3 structure were successfully formed on biochar surface. This led to the formation of iron nitrate hydrate (Fe(NO3)3·9H2O), which enabled higher nitrate adsorption performance than that of pristine biochar. Batch experiments showed that nitrate adsorption on the Fe-CC was stable and almost independent of experimental pH and temperature. Based on the Langmuir model results, the maximum nitrate adsorption capacity of Fe-CC was 32.33mg/g. Coexisting anions had negative influence on the adsorption performance. Findings of this work suggest that the modified biochar can be used in wastewater treatment to remove anions such as nitrate. Graphic abstract ᅟ.

Matrix Effect Assessment of an Ion Chromatographic Method to Determine Inorganic Anions in Wastewater

Inorganic anion monitoring is essential for bioreactor operation and is related for pollution control or energy and products recovery. However, there is a lack of studies validating methods for inorganic anions analyses in conditions compatible to those in bioreactor operations treating different types of wastewater. This paper provides a systematic statistical study and matrix-effect assessment for sugarcane vinasse, leachate, sewage and synthetic sewage. Sample preparation consisted of only a filtration and sample dilution. Cl−, NO2−, NO3−, PO43− and SO42− were determined in a Dionex ICS 5000® equipped with a chemical conductivity suppressor. Calibration curves were linear and well-adjusted between 2.5 and 50 mg L−1 for all the anions in all the tested matrices, except PO43− and SO42− in vinasse. A calibration range for PO43− in all tested matrices was 5.0 to 100 mg L−1, whereas a range from 5.0 mg L−1 to 50 mg L−1 was obtained for SO42− in vinasse. All the anions yielded recoveries in the range of 85–115% for all the tested matrices. Relative standard deviations lower than 10 and 2% were achieved for peak areas and retention times, respectively. A signal enhancement was observed for all the tested matrices and all the anions. The matrix effect level varied from −1.7 (NO2− in vinasse) to −33.9% (Cl− in leachate). Sewage was the less affected matrix, while leachate gave higher matrix effects. Validation results and the matrix effect assessment showed that a simple sample preparation is suitable for multi-elemental analyses of inorganic anions for complex environmental samples.

Density functional theory characterization of phosphate and sulfate adsorption on Fe-(hydr)oxide: Reactivity, pH effect, estimation of Gibbs free energies, and topological analysis of hydrogen bonds

Understanding adsorption of phosphate and sulfate on Fe-(hydr)oxide surfaces is important to predict the fate of these anions in wastewater and in the design of systems to remove and recover phosphates. Quantum chemical calculations were used to estimate relative Gibbs free energies of phosphate and sulfate adsorption like inner-sphere and outer-sphere complexes using three different simulated pH conditions (acid, intermediate, and basic). Bidentate binuclear surface complexes presented the most thermodynamically favorable mode of adsorption for both phosphate and sulfate with −94.4kJ/mol and −62.3kJ/mol, respectively, at acid pH condition. Topological analysis was done to understand how the Fe-(hydr)oxide surfaces are affected for the different types of adsorption of phosphate and sulfate. A classification of the OH⋯O hydrogen bonds (HBs) formed in all structures discriminating among the surface functional groups, solvation water molecules, and adsorbed molecules was done by the topological analysis of the electron density. HBs nature is mostly electrostatic which agrees with positive values of the Laplacian. This result indicates the existence of positive cooperative effects among these interactions which confers additional stabilization to the systems.

Characterization and use of functionalized carbon nanotubes for the adsorption of heavy metal anions

Carbon nanotubes (CNTs) have been chemically functionalized with various oxygen-containing surface groups. The feature of abundant oxygen-containing surface functional groups on the functionalized CNTs is characterized by X-ray photoelectron spectroscopy and temperature-programmed desorption analyslis. Results indicate that the functionalized CNTs have a superior adsorption capacity toward anionic chromate CrO 4 2-, a typical toxic heavy metal ion in waste water, as compared with the unmodified ones. The excellent adsorption ability of CrO 4 2- is attributed to the interaction of CrO 4 2- with the surface oxygen-containing functional groups on the modified CNTs. The functionalized CNTs can be potentially used as an alternatively viable and promising adsorbent for the removal of heavy metal anions in waste water.

Uncertainty of nitrate and sulphate measured by ion chromatography in wastewater samples

Abstract This paper presents an evaluation of measurement uncertainty regarding the results of anion (nitrate and sulphate) concentrations in wastewater. Anions were determined by ion chromatography (EN ISO 10304-2, 1996). The major sources of uncertainty regarding the measurements’ results were identified as contributions to linear least — square or weighted regression lines, precision, trueness, storage conditions, and sampling. Determination of anions in wastewater is very important for the purification procedure, especially the amount of nitrate in waste and potable waters. The determined expanded uncertainty was 6.1 % for nitrate anions and 8.3 % for sulphate anions. The difference between measurement uncertainties determined by the two methods, the weighted and linear least — square methods, is negligible.

リン酸イオン高選択性無機層状イオン交換体を用いた排水からのリン除去

The purpose of this study is to remove phosphorous in wastewater by using layer structure inorganic ion exchanger with high selectivity for phosphate anion(TPEX).The results obtained are as follows.1)TPEX showed large phosphate removal of 1.43-2.23mmol·g-1 in phosphorous concentrations of 1-800mgP·l-1. Maximum removal amount of phosphate ions was obtained around pH value of 7.0.2)The ion selectivity of various anions in wastewater were in the order of CO3>PO4>>SO4>>C1>>NO2>NO3.3)Residual concentrations of the phosphate ion from rural sewages treated with TPEX were less than 1mg·l-1.Talking the results obtained into account, TPEX has been expected as a promising inorganic phosphorous adsorbent.