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Abstract

Ag-Clinoptilolite/Polyethersulfone (PES/Clin/AgNPs) nanofiber was synthesized through the electrospinning method. The effect of solvent, the amount of Ag-Clinoptilolite, and PES were investigated. Parameters such as electric field, spinning distance, and concentration of the dope solution were studied in order to demonstrate their effects on the electrospinning ability and morphology of the nanofiber. The structure of PES/Clin/AgNPs nanofiber was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analyses. In the optimum conditions, the nanofibers could be prepared at the size of 250–800 nm. Then, their ability to remove chemical oxygen demand (COD) from real wastewater was studied. The result revealed about 85% removal of COD at pH = 10 and in 10 min for PES/Clin/AgNPs (25%). A successful fabrication method using low-cost natural zeolite and the green polymer was introduced. The reusability of the column was assessed.

Keywords

Chemical oxygen demand Ag-Clinoptilolite/Polyethersulfone electrospinning

Introduction

Nowadays, maintaining quality and adequate water resources to meet a society’s needs is a critical issue. Changes in lifestyle have caused different kinds of pollutions such as bacteria, organic materials, dyes, anion, and cation introduced in water. On the other hand, finding a best solution for the elimination of these pollutions has become a challenge for scientists. One of the most important issues in environmental pollution is the chemical oxygen demand (COD). COD is an important parameter to evaluate the concentration of organic contaminants in the water and wastewater.¹ Higher COD levels mean a greater amount of oxidizable organic material in the sample, which can reduce dissolved oxygen (DO) levels.² Residual food waste such as bottles and cans, antifreeze, and emulsified oils are all rich in COD and familiar sources of COD for industrial wastewater.³ Influent COD in normal domestic sewage is generally 600–900 mg/L, and it is then treated to at least 75–100 mg/L before discharge to minimize pollution potential. Treating of the COD is very challenging ⁴; some processes can help to reduce wastewater’s COD, such as using chemical materials.⁵ Nowadays, nanoparticles such as copper, zinc, silver, and zirconia are great and effective antibacterial agents⁶ that reduce COD due to their high particular surface area and interfacial activity. Literature reviews show that introducing it to solid substrates such as titanium dioxide, zinc oxide, and silica is helpful to reduce pollutants in large-scale industrial applications.⁷ Possessing some disadvantages, such as high energy requirements,⁸ toxic sludge,⁹ releasing of nanoparticle to environment,¹⁰ stability of adsorbents, and agglomeration of the nano-adsorbents during adsorption¹¹ process are still challenging issues for this absorbent. Zeolites have been applied in various procedures such as separation¹² and filtration¹³ due to their specific porous structures and mobility¹⁴ being useful to purified water.

In recent decades, a new type of membrane has recently been designed by combining polymeric materials with nanoparticles for water treatments^15,16 to overcome this challenge. The feed solution, which contains the species removed, passes through the membrane, and the impurities are retained at the surface or pores of the material in the membrane.^17–20 The hybrid membranes could control many parameters, such as their pore size, porosity, charge density, and mechanical stability.^21–24

Some polymers such as Polyethersulfone (PES), Polytetrafluoroethylene, Polypropylene, Polyvinylidene fluoride, Chitosan, and Cellulose acetate are popular hydrophobic membranes.^25–26

One of the individual engineering plastics is PES, which has higher efficiency.²⁷ Furthermore, PES membranes have good conductivity and selectivity.²⁸ So those features are a cause of using PES for hemodialysis,²⁹ hemofiltration,³⁰ and water treatment stages.³¹ Moreover, filtration often needs the membranes to provide sufficient mechanical stability and chemical and physical resistance in the diverse situations such as a broad range of temperature, humidity, mechanical vibration, shock, and reactive strength.³²

Today, electrospinning is known as an effectively produced nanofiber structure for a broader range of membranes.³³ A high-performance filter applied in the treatment and recycling of wastewater is electrospun due to the suitable fiber diameter being a significant parameter to determine the filter’s filtration feature.³⁴ The electrospun nanofibers have diverse individual attributes such as superior mechanical properties, particular surface area, significant porosity, and continuous fibers.³⁵ In addition, simplicity, low-cost effectiveness, and relatively excellent production rate are other advantages of this procedure. Therefore, electrospinning has been used in plenty of usages such as textile, catalyst, membrane, sensor, biomedical,³⁶ filtration, template, and removal of various heavy metal ions.^37,27

In this aim, for the first time, silver nanoparticle (Ag NPs) as a low-cost natural zeolite was added to clinoptilolite (Clin). Then, Clin/Ag NPs hybrid was introduced to the PES electrospun nanofibers using a sol–gel process to modify it. The PES/Clin/AgNPs were characterized with different techniques. Finally, we considered the removal of COD of wastewater in real wastewater.

Materials and methods

Materials

PES (Mw = 48,000 g/mol and density 1.37 g/cm³) and N, N-dimethylformamide (DMF) were purchased from Sigma-Aldrich. Natural zeolite (clinoptilolite) is from Semnan Iran. Sodium hydroxide (NaOH) pellets and silver nitrate (AgNO₃) (99.9%), and sodium tetrahydroborate (NaBH₄) (99%) were purchased from Merck company.

Characterization

The chemical compositions of the samples were evaluated by EDX (XFLASH 6130). The PES/Clin/AgNPs nanofiber structure was analyzed by FT-IR spectra Galaxy series FT-IR 5000 spectrometer with KBr tablet. The crystalline structures of samples were studied with the XRD, Model X-ray diffractometer (PW-1840) manufactured by Philips with a CuKα anode, and λ = 154 nm radiation. The morphologies of samples were investigated by SEM Emcrafts 1000 model. Sputter Coater for gold (Au) coating of non-conducting samples for SEM imaging was used. The thermal behaviors of sample were studied with a thermogravimetric analyzer (PerkinElmer TG/DT 6300 PYRIS TM Diamond model) in the temperature range of 30–600°C in a nitrogen atmosphere. The N₂ adsorption-desorption was analyzed by BET (Belsorp-Mini II). The elemental composition of sample was analyzed by XRF ARL 8410 model.

Methods

Synthesis of Ag/zeolite nanoparticles

To prepare Na/Clinoptilolite, 10 g of Clinoptilolite was added to a 2m NaOH solution, and the mixture was stirred in room conditions for 3 days, filtrated, and washed with distilled water, and was dried in a vacuum oven at 120°C for 3 h.³⁸ Then, 3g of Na/Clinoptilolite was introduced to 150 cm³ of AgNO₃ (0.03 m) and stirred for 3 h, Ag⁺/Clinoptilolite powder was filtered and washed and dried in a vacuum oven at 120°C. To reduce Ag⁺ to Ag⁰, 150 cm³ of NaBH₄ (0.024 m) was added to Ag⁺/Clinoptilolite powder and stirred at room conditions for 1 h. After, Ag/Clinoptilolite was filtered and washed with distillated water and dried in a vacuum oven at 120°C for 3 h (Figure 1).

Figure 1.

Schematic illustration of the synthesis of Ag/zeolite nanoparticles.

Preparation of Ag/zeolite/PES electrospun nanofibers

Based on Figure 2, PES was dissolved in DMF solvent at 60°C for 24 h until it formed a homogeneous solution.³⁹ Different concentration of (23, 20, 17, and 14.5 w/w %) PES solution were prepared, and the resulting material was mixed with 0.2 g nano-Ag/Clinoptilolite, which was homogenized by ultrasonication and stirred at 60°C for 12 h. The prepared solution was packed in a syringe as the spinneret and was injected into the spinneret with a needle. For output of direct-current (DC) voltages, the spinneret was fixed by high voltage (from 15 to 22 kV).

Figure 2.

Schematic illustration preparation of Ag/zeolite/PES electrospun nanofibers.

To obtain the optimal state for nanofibers produced by electrospinning, many essential parameters must be investigated. Voltage and injection rate are more significant, which need optimization relative to PES’s concentrations. Also, the flow of the polymeric solution through the metallic needle tip determines the morphology of the electrospun nanofibers. Uniform beadles electrospun nanofibers could be prepared via a critical flow rate for a polymeric solution.³⁹ Increasing the flow rate above the critical value could lead to formation of beads. Since the change in the flow rate affect the nanofiber formation and diameter, a minimum flow rate is preferred to maintain a balance between the leaving polymeric solution and the replacement of that solution with a new one during jet formation.⁴⁰ The construction of smaller-diameter nanofibers with an increase in the applied voltage is attributed to the stretching of the polymer solution in correlation with the charge repulsion within the polymer jet. All PES concentrations were considered in different ranges (voltage 22–15 kV and injection rate 2–0.5 mL/h). In the optimal state, nozzle clogging, fiber rupture, or polymer spraying do not occur, and uniform and continuous nanofibers are produced over a long period. The bold raw to find the best structure for nanofiber, characterized by SEM, is shown in Table 1. In addition, the effect of temperature change was investigated in ranges of 20–35°C. The high- temperature causes the solution to evaporate, and low temperature increases viscosity. Therefore, 30°C was the optimum temperature to find the best density for nanofiber. The distance between the metallic needle tip and collector plays an essential role in determining the morphology of an electrospun nanofiber. The nanofiber morphology could be easily affected by the distance because it depends on the deposition time, evaporation rate, and whipping or instability interval. Hence, every change on either side of the critical distance can affect the morphology of the nanofibers. Therefore, the distance between collector and spinneret was fixed. All PES solution was electrospun onto aluminum foil or non-woven support.

Table 1.

The optimum condition to find the best structure for nanofiber.

Concentrationa	Voltages (kV)	Injection rate (mL/h)	Distance (cm)	Temperature (ºC)
PES 14.5 wt%	17	0.4	15	30
PES 17 wt%	17.8	0.4	15	30
PES 20 wt%	18.5	0.5	15	30
PES 23 wt%	18.8	0.5	15	30

^aDMF solvent.

Reduction of chemical oxygen demand parameters

To measure COD parameters, the ASTM D1259 method was used, which is a valid global reference in laboratories approved by the environment organization.³⁸ This method’s basis is the oxidation of organic pollutants by K₂Cr₂O₇ and mercury catalyst HgSO₄ in the presence of silver sulfate (Ag₂SO₄). The vials, which contained a sample, were refluxed at 150°C for 2 h, and Cr (VI) was reduced to Cr (III). The oxidant excess was distinguished by a UV–Vis spectrophotometer set at 420–600 nm.⁴¹

Results and discussion

FT-IR analysis

Figure 3(a)–(c) show FT-IR spectra for the PES, nano-Ag/Clinoptilolite, and PES/Clin/AgNPs nanocomposite. The FT-IR PES nanofiber showed the bands at 1578 cm⁻¹, 1484 cm⁻¹, and 1406 cm⁻¹, ascribing the stretching vibration of integral benzene rings that are chemically stable. Moreover, PES nanofiber had weak absorbance near 1670 cm⁻¹, attributable to the stretching vibration of C = C of benzene rings. According to the spectrum of PES, two bands occurred about 1300 cm⁻¹, representing the asymmetrical stretching vibration of S = O bonds, and the symmetrical stretching vibration of those bonds appeared at 1146 cm⁻¹.⁴² The infrared spectrum of nano-Ag/Clinoptilolite (Figure 3(b)) consists of broadband in the range of 3300–3700 cm⁻¹ belonging to the surface hydroxyl groups. Moreover, the other area is in the field of 400–1200 cm⁻¹, which is due to the zeolite network’s tensile vibrations.

Figure 3.

FT-IR spectra of PES (a), nano-Ag/Clinoptilolite (b), PES/Clin/AgNPs nanocomposite (c).

In addition, it includes Si-O-Al flexural vibrations at 461 cm⁻¹ frequencies, symmetric vibrations at 741 cm⁻¹ and 795 cm⁻¹, and Si-O-Al chain vibrations at 1074 cm⁻¹.⁴³ The comparison of FT-IR spectra of PES/Clin/AgNPs with pure nano-Ag/Clinoptilolite and PES are show there aren't significant change respect to PES, which may be due to fine dispersing of zeolite on the polymer.⁴¹

X-ray diffraction analysis

X-ray diffraction patterns of Ag/Clinoptilolite and PES/Clin/AgNPs and pure PES are shown in Figure 4(a)–(c). Figure 4(a) shows the XRD pattern for nano-Ag/Clinoptilolite and lines appear at 2θ =9.9°,11.2°, 22.4°,31°, and 34.2° match with what was used to identify the phases present 1-25-1349 card numbers of Clinoptilolite (NaKCa)₆(Si₆Al₃₀)O₇₂ as principal crystalline phase about 80%. In addition, the weak lines related to nano-silver can be seen at 2Θ = 33.75° and 44.75° that are show with a circle. After introducing nano-Ag/Clinoptilolite to the polymer, which has an amorphous phase (Figure 4(c)), the official phase is amorphous due to the presence of large amount of PES, and some weak lines related to nano-Ag/Clinoptilolite are observed, which was the same as the result of other work.^44,45,46

Figure 4.

X-ray diffraction patterns of Ag-Clinoptilolite (a), PES/Clin/AgNPs (b), PES nanofiber (c).

Scanning electron microscopy images of the Ag-Clinoptilolite and PES/Clin/AgNPs nanocomposite with different concentrations of Ag-Clinoptilolite are shown in Figure 5(a)–(e), respectively. In the case of Ag-Clinoptilolite, the particle size is about 30–35 nm. PES/Clin/Ag nanocomposite shows the average fiber diameter increased from 250 nm to 800 nm which increased the percent from 23 to 14.5.

Figure 5.

SEM images of PES/zeolite with different PES/DMF ratio: Ag-Clinoptilolite (a), PES (b), 14.5 wt% (c), 17 wt% (d), 20 wt%(e), 23 wt%(f), (the scale bar is 1–10 μm, 0.5 mL/h Injection rate in 15 cm distance, 17–18.5 keV.

The images depict that Ag-Clinoptilolite particles are non-uniformly dispersed within the nanofibers. These images show that surface contact will increase and be suitable for applications requiring a high activity level. The best percentage of sulfone/Ag-Clinoptilolite polyether was found, indicating that high concentrations will increase the diameter of nanofibers and nozzle clogging and reduce the contact surface, and low concentrations will cause rosary grain structure and not suitable fibers. The chemical composition of the related compounds was evaluated by EDX for pure Clinoptilolite, Ag-Clinoptilolite, and PES/Clin/Ag nanocomposite (Figure 6(a)–(c)). The result shows that the Si/Al ratio for all samples is about four confirmed the presence of Clinoptilolite which is very close to XRF results (3.8). After introducing Ag and PES to Clinoptilolite, the peaks related to Ag, C and S can be observed indicating the presence of 20.96% Ag.

Figure 6.

EDX of (a) Clinoptilolite, (b) Ag-Clinoptilolite (c) PES/Clin/AgNPs.

Thermogravimetric analysis

Thermal analysis was carried out to examine the thermal stability of composite, and Figure 7(a) and (b) compare PES and PES/Clin/AgNPs nanocomposite. In two samples, the first step shows weight loss, which is corresponding to desorption of physical and chemical water before 180°C. In Figure 7(a), the second steps are related to the deformation and change of the polymer’s structure and thermal stability at about 420°C with weight loss of approximately 2.2%. Finally, a high weight lost after 420°C shows weight loss by the polymer chains' carbonization at about 600°C.⁴⁶ After the addition of nano Ag-Clinoptilolite to the polymer’s nanofiber, the degradation temperature rises from 420°C to 485°C. These results indicate that the thermal stability of the polymeric network increased by adding Ag-Clinoptilolite. This growth in thermal stability could be ascribed to the high thermal constancy, uniform distribution of zeolite particles, and the existence of an interaction between zeolite particles and polymer matrix.^27,47,48

Figure 7.

Thermogravimetric of PES (a), PES/Clin/AgNPs nanocomposite (b).

N₂ adsorption-desorption

The N₂ adsorption–desorption curves for Ag-Clinoptilolite and PES/Clin/AgNPs nanocomposite are illustrated in Figure 8. The result in the case of Ag-Clinoptilolite nitrogen adsorption–desorption isotherms shows a hysteresis loop at 0.6 to 0.9, and exhibiting characteristics of type IV isotherms for the sample confirmed the presence of mesoporous structures. In addition, a step can be observed at p/p₀ < .5 due to the microporous structure. The surface area is about 52 m²/g with a pore value of about 21 cm³, which reduced to 20 m²/g about 9.1 cm³, respectively, after introducing Ag-Clinoptilolite to PES. Decreasing the intensity of XRD lines, SEM images and IR spectra confirm that Ag-Clinoptilolite particle’s surfaces were covered by polyethersulfone.³⁵

Figure 8.

N₂ absorption/desorption isotherms diagrams, (a) Ag-Clinoptilolite, (b) PES/Clin/AgNPs nanocomposite.

Determination of chemical oxygen demand

Figure 9 shows the schematic illustration of the experiment column designed. Three real wastewater samples were related to Halal Poyan Company (Arak, Iran) with COD 500, 480, and 420 ppm were used. First, the wastewater samples crossed through the column with the different nanofiber layers, and COD was estimated by the mentioned method and the following formulate

(COD0 - CODt / COD0) × 100 = Reduce the percentage of COD

Figure 9.

Schematic illustration of experiment column designed.

where COD0 and CODt are the initial and equilibrium concentration of pollutants that are characterized by the use of COD, respectively.

The reducing COD in the presence of nanocomposite nanofibers is visible in Table 2. Each experiment was repeated three times, and the average of them was calculated. The result shows in the presence of nanofiber with estimated 3 and 4 layers being about,⁴⁹ 61, and 66% reduced the maximum number of COD.

Table 2.

% Removal of COD with use of polyethersulfone/Clin/Ag.

No	(NNCL)^a	pH	COD_{0 ppm}	(NNCL)	^bCOD_t ppm	(NNCL)	^bCOD_t ppm	(NNCL)	^bCOD_t ppm	% COD
1	––	8.45	500	1	455	2	390	3,4	295	49
2	––	8.40	480	1	350	2	242	3,4	230	61
3	––	8.42	420	1	310	2	225	3,4	140	66
4	0.2 g Ag/Clin	8.42	420	––	––	––	––	––	––	32

^aNumber of nanofiber composite layers.

^bNanofiber of PES/Clin/Ag nanocomposite containing 20% w/w of Ag-Clinoptilolite (0.2 g).

In fact, the presence of adsorbent increases free and active hydroxyl radicals and superoxide anions, which can significantly reduce the COD of wastewater because nanosilver was dispersed enough in the substrate. In addition, the sulfonyl group of the polymer and hydroxyl group of zeolites are suitable groups for trapping organic pollutants and interaction with nanosilver more comfortable with respect to powder (Table 2 entire 4). The pH of the wastewater solution is one of the essential factors in the adsorption or removal process. The effect of pH on the removal of COD is shown in Figure 10(a) for three samples with different COD of wastewater and using three layers of nanofiber of PES/Clin/AgNPs nanocomposite. The results show that the basic pH is better for decreasing COD (above 84% at pH = 10). It might be due to hydrogen ions themselves are strongly competing with organic pollutants and because pH determines the valence state of the ions and their precipitation process.

Figure 10.

(a) The effect of pH on the presence of removed COD for samples 1, 2, and 3 with COD are 500,400, and 420 ppm. (b) reusability of the column after three runs.

In addition, the deprotonations form of reactive sites such as sulfonyl groups of polymer and hydroxyl group of zeolite are responsible for the binding of pollutants (Scheme 1). To consider the reusability of PES/Clin/Ag nanofiber, the column was washed with distilled water three times, dried at room temperature (25°C), and used in three cycles. The result in Figure 10(b) shows that there is no significant change in the percent of removed COD (about 5%) which confirms the high activity of absorbent, and this result can prove the importance of this low-cost adsorbent in industry.

Scheme 1.

Mechanism for removal of COD

Comparison among the efficiency of PES/Clin/AgNPs with other polymer composites used for COD removal is reported in Table 3. The results show that besides the low-cost materials such as clinoptilolite to prepare this absorbent, in a mild condition, high presence of COD removal can be observed. In addition, the reusability, which confirms the stability of the absorbent, was not considered in other works considering that PES/Clin/Ag adsorbent can be used for several times without any significant change in its efficiency.

Table 3.

Comparison the efficiency of PES/Clin/AgNPs with other polymer composites.^50–52

Absorbent	Method	% Removal of COD	Time (min) and pH	Ref
SrCl2.6(H2O)-PAM	Batch (500 mg)	73	60 and 5	48
Chitosan-bentonite	Batch (1000 mg)	73	1200 and 4	49
PPy/RHA and PAn/RHA	Batch (500 mg)	About 85	20 and not consider	50
CSTPP/KC	Batch (600 mg)	88	30 and 4	51
Silver–zeolite–poly (acrylamide-co-acrylic acid	Batch (750 mg)	75	120 and 2	38
PES/cellulose/APTES	Membrane	88	Not consider and 8	52
This work	Membrane (300 mg)	85	10 and 10	—

Conclusion

In this study, different amounts of Ag-Clinoptilolite are incorporated onto polyethersulfone. High-quality electrospun PES method used in the presence of DMF as a solvent. Uniform fiber morphology (diameter: 250–800 nm) was obtained at PES concentrations from 23 to 14.5 wt% in DMF. With introducing Ag-Clinoptilolite, the average fiber diameter was slightly increased, and it trapped in polyethersulfone, confirmed by XRD and SEM result.

The PES/Clin/AgNPs nanocomposite has been used to remove COD in a real wastewater sample. Results showed that the removal percent of COD was approximately % 85 at pH = 10 in 10 min. In addition, PES/Clin/Ag nanocomposite could be used for several runs. This indicates the preservation of the nanoparticle-modified natural zeolite property and the addition of new and desirable properties to the nanofibers, being useful to wastewater industry.

Footnotes

Acknowledgments

Thanks to Arak University, and the Iranian Chemical Society’s zeolite and porous materials committee for supporting this work.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Mojgan Zendehdel

References

Domini

Hidalgo

Marken

, et al. Comparison of three optimized digestion methods for rapid determination of chemical oxygen demand: closed microwaves, open microwaves and ultrasound irradiation. Analytica Chim Acta 2006; 561: 210–217.

Khan

Ali

. Chemical analysis of air and water. In: Donat

Gilmar

(eds). Bioassays Advanced Methods and Applications. 1st ed. Amsterdams, Netherlands: Elsevier; 2018, pp. 21–39.

Wichmann

Otterpohl

. Review of the technological approaches for grey water treatment and reuses. Sci Total Environ 2009; 407: 3439–3449.

Zhou

Duan

, et al. COD Discharge Limits for Urban Wastewater Treatment Plants in China Based on Statistical Methods. Water 2018; 10: 777.

Chopra

Sharma

. Removal of turbidity, COD and BOD from secondarily treated sewage water by electrolytic treatment. Appl Water Sci 2013; 3: 125–132.

Mocanu

Rusen

Diacon

, et al. Antimicrobial properties of polysulfone membranes modified with carbon nanofibers and silver nanoparticles. Mater Chem Phys 2019; 223: 39–45.

Purcar

Rădiţoiu

, et al. Bilayer coatings based on silica materials and iron (III) phthalocyanine - Sensitized TiO2 photocatalyst. Mater Res Bull 2021; 138: 111222.

Sag

Kutsal

. Biosorption of heavy metals by Zoogloea ramigera: use of adsorption isotherms and a comparison of biosorption characteristics. Chem Eng J Biochem Eng J 1995; 60: 181–188.

Yurekli

. Removal of heavy metals in wastewater by using zeolite nano-particles impregnated polysulfone membranes. J Hazard Mater 2016; 309: 53–64.

10.

Hajipour

Fromm

Akbar Ashkarran

, et al. Antibacterial properties of nanoparticles. Trends Biotechnol 2012; 30: 499–511.

11.

Bahi

Shao

Mohseni

, et al. Membranes based on electrospun lignin-zeolite composite nanofibers. Separation Purif Technol 2017; 187: 207–213.

12.

Pincovschi

Modrogan

. The determination of mass transfer characteristics of a column for sulphur dioxide adsorption in 13 X zeolite working in unsteady-state regime. Revista de Chim 2018; 69: 2578–2580.

13.

Fathizadeh

Aroujalian

Raisi

. Effect of added NaX nano-zeolite into polyamide as a top thin layer of membrane on water flux and salt rejection in a reverse osmosis process. J Membr Sci 2011; 375: 88–95.

14.

Han

Zhang

Liu

, et al. Effect of NaA zeolite particle addition on poly(phthalazinone ether sulfone ketone) composite ultrafiltration (UF) membrane performance. J Membr Sci 2009; 345: 5–12.

15.

Rad

Momeni

Ghazani

, et al. Removal of Ni2+ and Cd2+ ions from aqueous solutions using electrospun PVA/zeolite nanofibrous adsorbent. Chem Eng J 2014; 256: 119–127.

16.

Alipour

Azari

. COD removal from industrial spent caustic wastewater: a review. J Environ Chem Eng 2020; 8: 103678.

17.

Thakur

Voicu

. Recent advances in cellulose and chitosan based membranes for water purification: a concise review. Carbohydr Polym 2016; 146: 148–165.

18.

Ghaee

Shariaty-Niassar

Barzin

, et al. Preparation of chitosan/cellulose acetate composite nanofiltration membrane for wastewater treatment. Desalination Water Treat 2016; 57: 14453–14460.

19.

Caprarescu

Vaireanu

Cojocaru

. 3-cell electrodialysis system for the removal of copper ions from electroplating wastewater. J Optoelectron Adv Mater 2011; 5: 1346–1351.

20.

Caprarescu

Miron

Purcar

, et al. Commercial gooseberry buds extract containing membrane for removal of methylene blue dye from synthetic wastewaters. Revista de Chim 2017; 68: 1757–1762.

21.

Luntraru

Gales

Iarca

, et al. Synthesis and characterization of magnetite – titanium dioxide - 4-Benzene-azo-α-naphthylamine and methylene blue composites. J Optoelectron Adv Mater 2011; 5: 1229–1232.

22.

Chu

Hasiao

. Role of polymers in breakthrough technologies for water purification. J Polym Sci 2009; 47: 2435.

23.

Koushkbaghi

Jamshidifard

ZabihiSahebi

, et al. Synthesis of ethylcellulose/aluminosilicate zeolite nanofibrous membranes for oil-water separation and oil absorption. J Cellulose 2016; 26: 9787–9801.

24.

Cheremisionoff

. Handbook of Water and Wastewater Treatment Technology. Boston, MA: Butterworth Heinemann, 2002.

25.

Wang

Nikiforov

, et al. Atmospheric-pressure plasma assisted engineering of polymer surfaces: from high hydrophobicity to superhydrophilicity. Appl Surf Sci 2021; 535: 147032.

26.

Mao

Huang

Meng

, et al. Roughness-enhanced hydrophobic graphene oxide membrane for water desalination via membrane distillation. J Membr Sci 2020; 611: 118364.

27.

Simona

Raluca

Anita-Laura

, et al. Synthesis, characterization and efficiency of new organically modified montmorillonite polyethersulfone membranes for removal of zinc ions from wastewasters. Appl Clay Sci 2017; 137: 135–142.

28.

Cao

Chung

T-S

Chen

, et al. The study of elongation and shear rates in spinning process and its effect on gas separation performance of Poly(ether sulfone) (PES) hollow fiber membranes. Chem Eng Sci 2004; 59: 1053–1062.

29.

Raharjo

Fahmi

Wafiroh

, et al. Incorporation of imprinted-zeolite to polyethersulfone/cellulose acetate membrane for creatinine removal in hemodialysis treatment. J Jurnal Teknologi 2019; 81: 137–144.

30.

Huang

Z-M

Zhang

Y-Z

Kotaki

, et al. A review on polymer nanofibers by electrospinning and their applications in nanocomposites. Composites Sci Technol 2003; 63: 2223–2253.

31.

Chen

Zhang

, et al. One-step electrospinning of negatively-charged polyethersulfone nanofibrous membranes for selective removal of cationic dyes. J Taiwan Inst Chem Eng 2017; 0: 1–10.

32.

Pascu

D-E

Miron

Pascu-Neagu

, et al. Fabrication, characterization, and modelling of polysulfone composite membranes with enhanced adsorbent capabilities. Separation Sci Technol 2016; 51: 2628–2638.

33.

Sagitha

Reshmi

Manaf

, et al. Development of nanocomposite membranes by electrospun nanofibrous materials. Nanocomposite Membranes Water Gas Separation 2020; 0: 199–218.

34.

Chen

Huang

Liu

, et al. Functionalized electrospun nanofiber membranes for water treatment: a review. Sci Total Environ 2020; 739: 139944.

35.

Assar

Meysami

Zare

. Morphology analysis and characterization of clinoptilolite/polyvinylpyrrolidone-zeolite composite nanofibers. J Mater Eng Perform 2020; 29: 4233–4240.

36.

Wang

G-J

Chu

L-Y

Chen

W-M

, et al. A porous microcapsule membrane with straight pores for the immobilization of microbial cells. J Membr Sci 2005; 252: 279–284.

37.

Zhu

Zheng

Y-M

Zhang

B-G

, et al. A critical review on the electrospun nanofibrous membranes for the adsorption of heavy metals in water treatment. J Hazard Mater 2021; 401: 123608.

38.

Zendehdel

Zendehnam

Hoseini

, et al. Investigation of removal of chemical oxygen demand (COD) wastewater and antibacterial activity of nanosilver incorporated in poly (acrylamide-co-acrylic acid)/NaY zeolite nanocomposite. Polym Bull 2015; 72: 1281–1300.

39.

Lin

Yao

Yang

, et al. Preparation of poly(ether sulfone) nanofibers by gas-jet/electrospinning. J Appl Polym Sci 2008; 107: 909–917.

40.

Haider

Kang

I-K

. A comprehensive review summarizing the effect of electrospinning parameters and potential applications of nanofibers in biomedical and biotechnology. Arabian J Chem 2018; 11: 1165–1188.

41.

Ghiggi

Pollo

Cardozo

NSM

, et al. Preparation and characterization of polyethersulfone/N-phthaloyl-chitosan ultrafiltration membrane with antifouling property. Eur Polym J 2017; 92: 61–70.

42.

Farnam

Mukhtar

Shariff

. Analysis of the influence of CMS variable percentages on pure PES membrane gas separation performance. Proced Eng 2016; 148: 1206–1212.

43.

Favvas

Tsanaktsidis

Sapalidis

, et al. Clinoptilolite, a natural zeolite material: structural characterization and performance evaluation on its dehydration properties of hydrocarbon-based fuels. Microporous Mesoporous Mater 2016; 225: 385–391.

44.

Velu

Arthanareeswaran

Lade

. Removal of organic and inorganic substances from industry wastewaters using modified aluminosilicate-based polyethersulfone ultrafiltration membranes. Environ Prog Sustain Energ 2017; 36: 1612–1620.

45.

Zendehdel

Barati

Alikhani

. Removal of heavy metals from aqueous solution by poly(acrylamide-co-acrylic acid) modified with porous materials. Polym Bull 2011; 67: 343–360.

46.

Abedini

. Enhanced antifouling properties of poly(ethersulfone) nano-composite membrane filled with nano-clay particles. Polym Bull 2018; 76: 1737–1753.

47.

Qian

Zhou

, et al. Effect of the grafted silane on the dispersion and orientation of clay in polyethylene nanocomposites. Polym Compos 2009; 30: 1234–1242.

48.

Al-Ani

Rajab

Ismael

. A novel composite polymer for chemical oxygen demand and total suspended solids removal. In: International Conference on Developments in eSystems Engineering (DeSE), Kazan, Russia, 23 April 2020, Paper no. 19557251.

49.

Ligaray

Futalan

De Luna

, et al. Removal of chemical oxygen demand from thin-film transistor liquid-crystal display wastewater using chitosan-coated bentonite: Isotherm, kinetics and optimization studies. J Clean Prod 2018; 175: 145–154.

50.

Ghorbani

Eisazadeh

. Removal of COD, color, anions and heavy metals from cotton textile wastewater by using polyaniline and polypyrrole nanocomposites coated on rice husk ash. Composites B Eng 2013; 45: 1–7.

51.

Jawad

Abdulhameed

. Facile synthesis of crosslinked chitosan-tripolyphosphate/kaolin clay composite for decolourization and COD reduction of remazol brilliant blue R dye: optimization by using response surface methodology. Colloids Surf APhysicochem Eng Aspects 2020; 605: 125329.

52.

Jonoobi

Ashori

Siracusa

. Characterization and properties of polyethersulfone/modified cellulose nanocrystals nanocomposite membranes. Polym Test 2019; 76: 333–339.

Electrospun polyethersulfone/Ag-Clinoptilolite to remove chemical oxygen demand from real wastewater

Abstract

Keywords

Introduction

Materials and methods

Materials

Characterization

Methods

Synthesis of Ag/zeolite nanoparticles

Preparation of Ag/zeolite/PES electrospun nanofibers

Reduction of chemical oxygen demand parameters

Results and discussion

FT-IR analysis

X-ray diffraction analysis

Thermogravimetric analysis

N2 adsorption-desorption

Determination of chemical oxygen demand

Conclusion

Footnotes

Acknowledgments

Declaration of Conflicting Interests

Funding

ORCID iD

References

N₂ adsorption-desorption