Editorial

8 pages, 213 KiB

Open AccessEditorial

Adsorption Technology for Water and Wastewater Treatments

by Hai Nguyen Tran

Water 2023, 15(15), 2857; https://doi.org/10.3390/w15152857 - 07 Aug 2023

Cited by 2 | Viewed by 2362

This Special Issue includes 12 research papers on the development of various materials for adsorbing different contaminants in water, such as Sb, Cr(VI), Cu(II), Zn(II), fluorine, phenol, dyes (indigo carmine, Congo red, methylene blue, and crystal violet), and drugs (dlevofloxacin, captopril, and diclofenac, [...] Read more.

This Special Issue includes 12 research papers on the development of various materials for adsorbing different contaminants in water, such as Sb, Cr(VI), Cu(II), Zn(II), fluorine, phenol, dyes (indigo carmine, Congo red, methylene blue, and crystal violet), and drugs (dlevofloxacin, captopril, and diclofenac, and paracetamol). The commercial, natural, and synthetic materials used as adsorbents comprise commercial activated carbon, natural clay and montmorillonite, biosorbent based on sugarcane bagasse or algal, graphene oxide, graphene oxide-based magnetic nanomaterial, mesoporous Zr-G-C₃N₄ nanomaterial, nitrogen-doped core–shell mesoporous carbonaceous nano-sphere, magnetic Fe-C-N composite, polyaniline-immobilized ZnO nanorod, and hydroxy-iron/acid–base-modified sepiolite composite. Various operational conditions are evaluated under batch adsorption experiments, such as pH, NaCl, solid/liquid ratio, stirring speed, contact time, solution temperature, initial adsorbate concentration. The re-usability of laden materials is evaluated through adsorption–desorption cycles. Adsorption kinetics, isotherm, thermodynamics, and mechanisms are studied and discussed. Machine learning processes and statistical physics models are also applied in the field of adsorption science and technology. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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14 pages, 3358 KiB

Open AccessArticle

Adsorption-Reduction of Cr(VI) with Magnetic Fe-C-N Composites

by Xu Liu, Huilai Liu, Kangping Cui, Zhengliang Dai, Bei Wang, Rohan Weerasooriya and Xing Chen

Water 2023, 15(12), 2290; https://doi.org/10.3390/w15122290 - 19 Jun 2023

Cited by 3 | Viewed by 1574

Abstract

In this study, the iron-based carbon composite (hereafter FCN-x, x = 0, 400, 500, and 600 calcination) was synthesized by a simple high-temperature pyrolysis method using iron-containing sludge coagulant generated from wastewater treatment settling ponds in chemical plants. The FCN-x was used for [...] Read more.

In this study, the iron-based carbon composite (hereafter FCN-x, x = 0, 400, 500, and 600 calcination) was synthesized by a simple high-temperature pyrolysis method using iron-containing sludge coagulant generated from wastewater treatment settling ponds in chemical plants. The FCN-x was used for the adsorptive reduction of aqueous phase Cr(VI) effectively. The FCN-x was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier infrared spectrometer (FT-IR), X-ray photoelectron spectrometer (XPS), and Brunauer-Emmett-Teller theory (BET). FCN-x adsorption of Cr(VI) was examined in batch experiments using CrO₄²⁻ as a function of physicochemical parameters. The chemical kinetics of Cr(VI) adsorption by FCN-500 were modeled by 1st and 2nd order empirical pseudo kinetics. Based on these experiments, FCN-500 has been selected for further studies on Cr(VI) adsorptive reduction. The maximum Cr(VI) adsorption by FCN-500 was 52.63 mg/g showing the highest removal efficiency. The Cr(VI) adsorption by the FCN-500 was quantified by the Langmuir isotherm. XPS result confirmed the reduction of Cr(VI) to Cr(III) by the FCN-500. The iron-based carbon composites have high reusability and application potential in water treatment. The electroplating wastewater with 117 mg/L Cr(VI) was treated with FCN-500, and 99.93% Cr(VI) was removed within 120 min, which is lower than the national chromium emission standard of the People’s Republic of China. This work illustrates the value-added role of sludge generated from dye chemical plants to ensure environmental sustainability. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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14 pages, 2703 KiB

Open AccessArticle

Algae and Hydrophytes as Potential Plants for Bioremediation of Heavy Metals from Industrial Wastewater

by Naila Farid, Amin Ullah, Sara Khan, Sadia Butt, Amir Zeb Khan, Zobia Afsheen, Hamed A. El-Serehy, Humaira Yasmin, Tehreem Ayaz and Qurban Ali

Water 2023, 15(12), 2142; https://doi.org/10.3390/w15122142 - 06 Jun 2023

Cited by 4 | Viewed by 2131

Abstract

Aquatic bodies contaminated by heavy metals (HMs) are one of the leading issues due to rapidly growing industries. The remediation of using algae and hydrophytes acts as an environmentally friendly and cost effective. This study was performed to investigate the pollution load, especially [...] Read more.

Aquatic bodies contaminated by heavy metals (HMs) are one of the leading issues due to rapidly growing industries. The remediation of using algae and hydrophytes acts as an environmentally friendly and cost effective. This study was performed to investigate the pollution load, especially HMs, in the wastewater of the Gadoon Industrial Estate and to utilize the hydrophytes (Typha latifolia (TL) and Eicchornia crassipes (EI)) and algae (Zygnema pectiantum (ZP) and Spyrogyra species (SS)) as bioremediators. The wastewater was obtained and assessed for physiochemical parameters before treating with the selected species. The pot experiment was performed for 40 days. Then the wastewater samples and selected species were obtained from each pot to analyze the metal removal efficiency and assess for metal concentrations using atomic absorption spectrophotometry. The dissolved oxygen (DO; 114 mg/L), total suspended solids (TSS; 89.30 mg/L), electrical conductivity (EC; 6.35 mS/cm), chemical oxygen demand (COD) (236 mg/L), biological oxygen demand (BOD; 143 mg/L), and total dissolved solids (TDS; 559.67 mg/L), pH (6.85) were analyzed. The HMs were noted as Zn (5.73 mg/L) and Cu (7.13 mg/L). The wastewater was then treated with the species, and significant reductions were detected in physicochemical characteristics of the wastewater such as DO (13.15–62.20%), TSS (9.18–67.99%), EC (74.01–91.18%), COD (25.84–73.30%), BOD (21.67–73.42%), and TDS (14.02–95.93%). The hydrophytes and algae removed up to 82.19% of the Zn and 85.13% of the Cu from the wastewater. The study revealed that the hydrophytes and algae significantly decreased the HM levels in the wastewater (p ≤ 0.05). The study found TL, EI, ZP, and SS as the best hyper accumulative species for Zn and Cu removal from wastewater. The HMs were removed in the order of Cu > Zn. The most efficient removal for Cu was found by Typha latifolia and Zn by Zygnema pectiantum. It was concluded that bioremediation is an environmentally friendly and cost-effective technique that can be used for the treatment of wastewater due to the efficiency of algae and hydrophytes species in terms of HM removal. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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20 pages, 5686 KiB

Open AccessArticle

In Situ Polyaniline Immobilized ZnO Nanorods for Efficient Adsorptive Detoxification of Cr (VI) from Aquatic System

by Fahad A. Alharthi, Riyadh H. Alshammari and Imran Hasan

Water 2023, 15(10), 1949; https://doi.org/10.3390/w15101949 - 21 May 2023

Cited by 4 | Viewed by 1813

Abstract

The elimination of toxic heavy metal ions from wastewater has been found to be of great importance in human as well marine animal wellbeing. Among various heavy metals, Cr (VI) has been found to be one of the highly toxic and carcinogenic heavy [...] Read more.

The elimination of toxic heavy metal ions from wastewater has been found to be of great importance in human as well marine animal wellbeing. Among various heavy metals, Cr (VI) has been found to be one of the highly toxic and carcinogenic heavy metals which are found to be dissolved in the water stream, the urgent treatment of which needs to be a priority. The present study demonstrates the fabrication of zinc oxide nanorods (ZnO NRs) and an immobilized polyaniline nanorod (ZnO@PAni NR) composite through an in situ free radical polymerization reactions. The material synthesis and purity were verified by X-ray diffractometer (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), energy dispersive spectroscope (EDS), and transmission electron microscope (TEM). Further, ZnO@PAni NRs were applied as an adsorbent for Cr (VI) in the aquatic system and exhibited a tremendous removal efficiency of 98.76%. The impact of operating parameters such as dose effect and pH on adsorption properties were studied. The uptake mechanism of Cr (VI) by ZnO@PAni was best explained by pseudo-second-order reaction, which suggested that the adsorption of Cr (VI) by the synthesized adsorbent material was processed by chemisorption, i.e., through formation of chemical bonds. The adsorption process proved viable and endothermic thermodynamically, and best supported by a Langmuir model, suggesting a monolayer formation of Cr (VI) on the surface of ZnO@PAni NRs. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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24 pages, 7229 KiB

Open AccessArticle

Comparison of Phenol Adsorption Property and Mechanism onto Different Moroccan Clays

by Younes Dehmani, Dison S. P. Franco, Jordana Georgin, Taibi Lamhasni, Younes Brahmi, Rachid Oukhrib, Belfaquir Mustapha, Hamou Moussout, Hassan Ouallal and Abouarnadasse Sadik

Water 2023, 15(10), 1881; https://doi.org/10.3390/w15101881 - 16 May 2023

Cited by 5 | Viewed by 1444

Abstract

This study focuses on the removal of phenol from aqueous media using Agouraï clay (Fes-Meknes-Morocco region) and Geulmima clay (Draa Tafilalet region). The characterization of the clay by Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), N2 adsorption (BET), Scanning Electron Microscopy (SEM), [...] Read more.

This study focuses on the removal of phenol from aqueous media using Agouraï clay (Fes-Meknes-Morocco region) and Geulmima clay (Draa Tafilalet region). The characterization of the clay by Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), N2 adsorption (BET), Scanning Electron Microscopy (SEM), and Thermogravimetric and differential thermal analysis (DTA/GTA) indicates that it is mainly composed of quartz, kaolinite, and illite. The results showed that raw Clay Agourai (RCA) and raw Clay Geulmima (RCG) adsorbed phenol very quickly and reached equilibrium after 30 min. Thermodynamic parameters reveal the physical nature of the adsorption, the spontaneity, and the sequence of the process. However, the structure and structural characterization of the solid before and after phenol adsorption indicated that the mechanism of the reaction was electrostatic and that hydrogen bonding played an important role in RCG, while kinetic modeling showed the pseudo-second-order model dynamics. The physics-statistics modeling was employed for describing the isotherm adsorption for both systems. It was found that the monolayer model with two different energy sites best describes adsorption irrespective of the system. The model indicates that the receptor density of each clay direct influences the adsorption capacity, demonstrating that the composition of the clay is the main source of the difference. Thermodynamic simulations have shown that the adsorption of phenol is spontaneous and endothermic, irrespective of the system. In addition, thermodynamic simulations show that the RCG could be adsorbed even further since the equilibrium was not achieved for any thermodynamic variable. The strength of this study lies in the determination of the adsorption mechanism of phenol on clay materials and the optimum values of temperature and pH. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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17 pages, 2616 KiB

Open AccessArticle

Factorial Design Statistical Analysis and Optimization of the Adsorptive Removal of COD from Olive Mill Wastewater Using Sugarcane Bagasse as a Low-Cost Adsorbent

by Fatima Elayadi, Mounia Achak, Wafaa Boumya, Sabah Elamraoui, Noureddine Barka, Edvina Lamy, Nadia Beniich and Chakib El Adlouni

Water 2023, 15(8), 1630; https://doi.org/10.3390/w15081630 - 21 Apr 2023

Cited by 5 | Viewed by 2125

Abstract

This work highlights the elimination of chemical oxygen demand (COD) from olive mill wastewater using sugarcane bagasse. A 2⁵⁻¹ fractional factorial design of experiments was used to obtain the optimum conditions for each parameter that influence the adsorption process. The influence of [...] Read more.

This work highlights the elimination of chemical oxygen demand (COD) from olive mill wastewater using sugarcane bagasse. A 2⁵⁻¹ fractional factorial design of experiments was used to obtain the optimum conditions for each parameter that influence the adsorption process. The influence of the concentration of sugarcane bagasse, solution pH, reaction time, temperature, and agitation speed on the percent of COD removal were considered. The design experiment describes a highly significant second-order quadratic model that provided a high removal rate of 55.07% by employing optimized factors, i.e., a temperature of 60 °C, an adsorbent dose of 10 g/L, a pH of 12, a contact time of 1 h, and a stirring speed of 80 rpm. The experimental data acquired at optimal conditions were confirmed using several isotherms and kinetic models to assess the solute interaction behavior and kind of adsorption. The results indicated that the experimental data were properly fitted with the pseudo-first-order kinetic model, whereas the Langmuir model was the best model for explaining the adsorption equilibrium. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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14 pages, 1490 KiB

Open AccessArticle

Applying Linear Forms of Pseudo-Second-Order Kinetic Model for Feasibly Identifying Errors in the Initial Periods of Time-Dependent Adsorption Datasets

by Hai Nguyen Tran

Water 2023, 15(6), 1231; https://doi.org/10.3390/w15061231 - 21 Mar 2023

Cited by 15 | Viewed by 5642

Abstract

Initial periods of adsorption kinetics play an important role in estimating the initial adsorption rate and rate constant of an adsorption process. Several adsorption processes rapidly occur, and the experimental data of adsorption kinetics under the initial periods can contain potential errors. The [...] Read more.

Initial periods of adsorption kinetics play an important role in estimating the initial adsorption rate and rate constant of an adsorption process. Several adsorption processes rapidly occur, and the experimental data of adsorption kinetics under the initial periods can contain potential errors. The pseudo-second-order (PSO) kinetic model has been popularly applied in the field of adsorption. The use of the nonlinear optimization method to obtain the parameters of the PSO model can minimize error functions during modelling compared to the linear method. However, the nonlinear method has limitations in that it cannot directly recognize potential errors in the experimental points of time-dependent adsorption, especially under the initial periods. In this study, for the first time, the different linear types (Types 1–6) of the PSO model are applied to discover the error points under the initial periods. Results indicated that the fitting method using its linear equations (Types 2–5) is really helpful for identifying the error (doubtful) experimental points from the initial periods of adsorption kinetics. The imprecise points lead to low adjusted R² (adj-R²), high reduced χ² (red-χ²), and high Bayesian information criterion (BIC) values. After removing these points, the experimental data were adequately fitted with the PSO model. Statistical analyses demonstrated that the nonlinear method must be used for modelling the PSO model because its red-χ² and BIC were lower than the linear method. Type 1 has been extensively applied in the literature because of its very high adj-R² value (0.9999) and its excellent fitting to experimental points. However, its application should be limited because the potential errors from experimental points are not identified by this type. For comparison, the other kinetic models (i.e., pseudo-first-order, pseudo-nth-order, Avrami, and Elovich) are applied. The modelling result using the nonlinear forms of these models indicated that the fault experimental points from the initial periods were not detected in this study. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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19 pages, 7151 KiB

Open AccessArticle

Mesoporous Zr-G-C₃N₄ Sorbent as an Exceptional Cu (II) Ion Adsorbent in Aquatic Solution: Equilibrium, Kinetics, and Mechanisms Study

by Lotfi Khezami, Abueliz Modwi, Kamal K. Taha, Mohamed Bououdina, Naoufel Ben Hamadi and Aymen Amine Assadi

Water 2023, 15(6), 1202; https://doi.org/10.3390/w15061202 - 20 Mar 2023

Cited by 6 | Viewed by 1820

Abstract

A mesoporous Zr-G-C₃N₄ nanomaterial was synthesized by a succinct-step ultrasonication technique and used for Cu²⁺ ion uptake in the aqueous phase. The adsorption of Cu²⁺ was examined by varying the operating parameters, including the initial metal concentration, contact [...] Read more.

A mesoporous Zr-G-C₃N₄ nanomaterial was synthesized by a succinct-step ultrasonication technique and used for Cu²⁺ ion uptake in the aqueous phase. The adsorption of Cu²⁺ was examined by varying the operating parameters, including the initial metal concentration, contact time, and pH value. Zr-G-C₃N₄ nanosorbent displays graphitic carbon nitride (g-C₃N₄) and ZrO₂ peaks with a crystalline size of ~14 nm, as determined by XRD analysis. The Zr-G-C₃N₄ sorbent demonstrated a BET-specific surface area of 95.685 m²/g and a pore volume of 2.16 × 10⁻⁷ m³·g⁻¹. Batch mode tests revealed that removing Cu (II) ions by the mesoporous Zr-G-C₃N₄ was pH-dependent, with maximal removal achieved at pH = 5. The adsorptive Cu²⁺ ion process by the mesoporous nanomaterial surface is well described by the Langmuir isotherm and pseudo-second-order kinetics model. The maximum adsorption capacity of the nanocomposite was determined to be 2.262 mol·kg⁻¹ for a contact time of 48 min. The results confirmed that the fabricated mesoporous Zr-G-C₃N₄ nanomaterial is effective and regenerable for removing Cu²⁺ and could be a potent adsorbent of heavy metals from aqueous systems. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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21 pages, 7179 KiB

Open AccessArticle

Montmorillonite-Based Natural Adsorbent from Colombia for the Removal of Organic Pollutants from Water: Isotherms, Kinetics, Nature of Pollutants, and Matrix Effects

by Marcela Paredes-Laverde, Diego F. Montaño and Ricardo A. Torres-Palma

Water 2023, 15(6), 1046; https://doi.org/10.3390/w15061046 - 09 Mar 2023

Cited by 4 | Viewed by 1658

Abstract

The presence of dyes and pharmaceuticals in natural waters is a growing concern worldwide. To address this issue, the potential of montmorillonite (MMT), an abundant clay in Colombia, was assessed for the first time for the removal of various dyes (indigo carmine (IC), [...] Read more.

The presence of dyes and pharmaceuticals in natural waters is a growing concern worldwide. To address this issue, the potential of montmorillonite (MMT), an abundant clay in Colombia, was assessed for the first time for the removal of various dyes (indigo carmine (IC), congo red (CR), methylene blue (MB) and crystal violet (CV)) and pharmaceuticals (levofloxacin and diclofenac) from water. Initially, the MMT was characterized. TGA and FTIR showed OH groups and water adsorbed onto MMT. XRD showed an interlayer spacing of 11.09 Å and a BET surface area of 82.5 m²g⁻¹. SEM/EDS revealed a typical flake surface composed mainly of Si and O. Subsequently, the adsorbent capacity of MMT was evaluated for the removal of the pollutants. Adsorption isotherms showed a fit to the Langmuir model, which was confirmed by the Redlich–Peterson isotherm, indicating a monolayer-type adsorption. Furthermore, adsorption kinetics were best described by the pseudo-second-order model. Adsorption capacity (for dyes CV > MB > CR > IC) was associated with the attractive forces between the contaminants and MMT (PZC 2.6). Moreover, the findings evidenced that MMT can remove MB, CR, CV, and levofloxacin by electrostatic attractions and hydrogen bonding, while for IC and diclofenac only hydrogen bonding takes place. It was shown that MMT was most cost-effective at removing CV. Additionally, the material was able to be reused. Finally, the MMT efficiently removed CV in textile wastewater and levofloxacin in urine due to the positive charge of the pollutants and the low PZC of MMT. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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13 pages, 3383 KiB

Open AccessArticle

Nitrogen-Doped Core-Shell Mesoporous Carbonaceous Nanospheres for Effective Removal of Fluorine in Capacitive Deionization

by Yubo Zhao, Kexun Li, Bangsong Sheng, Feiyong Chen and Yang Song

Water 2023, 15(3), 608; https://doi.org/10.3390/w15030608 - 03 Feb 2023

Cited by 2 | Viewed by 1819

Abstract

Fluorine pollution of wastewater is a global environmental problem. Capacitive deionization has unique advantages in the defluorination of fluorine-containing wastewater; however, the low electrosorption capacity significantly restricts its further development. To overcome this limitation, nitrogen-doped core-shell mesoporous carbonaceous nanospheres (NMCS) were developed in [...] Read more.

Fluorine pollution of wastewater is a global environmental problem. Capacitive deionization has unique advantages in the defluorination of fluorine-containing wastewater; however, the low electrosorption capacity significantly restricts its further development. To overcome this limitation, nitrogen-doped core-shell mesoporous carbonaceous nanospheres (NMCS) were developed in this study based on structural optimization and polarity enhancement engineering. The maximal electrosorption capacity of NMCS for fluorine reached 13.34 mg g⁻¹, which was 24% higher than that of the undoped counterpart. NMCS also indicated excellent repeatability evidenced by little decrease of electrosorption capacity after 10 adsorption-regeneration cycles. According to material and electrochemical measurements, the doping of nitrogen into NMCS resulted in the improvement of physicochemical properties such as conductivity and wettability, the amelioration of pore structure and the transformation of morphology from yolk-shell to core-shell structure. It not only facilitated ion transportation but also improved the available adsorption sites, and thus led to enhancement of the defluorination performance of NMCS. The above results demonstrated that NMCS would be an excellent electrode material for high-capacity defluorination in CDI systems. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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23 pages, 4056 KiB

Open AccessFeature PaperArticle

Predictive Model Based on K-Nearest Neighbor Coupled with the Gray Wolf Optimizer Algorithm (KNN_GWO) for Estimating the Amount of Phenol Adsorption on Powdered Activated Carbon

by Meriem Zamouche, Mouchira Chermat, Zohra Kermiche, Hichem Tahraoui, Mohamed Kebir, Jean-Claude Bollinger, Abdeltif Amrane and Lotfi Mouni

Water 2023, 15(3), 493; https://doi.org/10.3390/w15030493 - 26 Jan 2023

Cited by 11 | Viewed by 2037

Abstract

In this work, the adsorption mechanism of phenol on activated carbon from aqueous solutions was investigated. Batch experiments were performed as a function of adsorbent rate, solution temperature, phenol initial concentration, stirring speed, and pH. The optimal operating condition of phenol adsorption were: [...] Read more.

In this work, the adsorption mechanism of phenol on activated carbon from aqueous solutions was investigated. Batch experiments were performed as a function of adsorbent rate, solution temperature, phenol initial concentration, stirring speed, and pH. The optimal operating condition of phenol adsorption were: mass/volume ratio of 0.6 g.L⁻¹, temperature of 20 °C and stirring speed of 300 rpm. The equilibrium data for the adsorption of phenol were analyzed by Langmuir, Freundlich, and Temkin isotherm models. It was found that the Freundlich and Temkin isotherm models fitted well the phenol adsorption on the activated carbon and that the adsorption process is favorable. The Langmuir equilibrium isotherm provides a maximum adsorption of 156.26 mg.g⁻¹ at 20 °C. The pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Boyd models were used to fit the kinetic data. The adsorption kinetics data were well described by the pseudo-second-order model. The kinetic was controlled by the external diffusion by macropore and mesopore, as well as by the micropore diffusion. The thermodynamic study revealed the exothermic and spontaneous nature of phenol adsorption on activated carbon with increased randomness at the solid-solution interface. On the other hand, a very large model based on the optimization parameters of phenol adsorption using k-nearest neighbor coupled with the gray wolf optimizer algorithm was launched to predict the amount of phenol adsorption. The KNN_GWO model showed an advantage in giving more precise values related to very high statistical coefficients (R = 0.9999, R² = 0.9998 and R²_adj = 0.9998) and very low statistical errors (RMSE = 0, 0070, MSE = 0.2347 and MAE = 0.2763). These advantages show the efficiency and performance of the model used. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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19 pages, 7333 KiB

Open AccessArticle

Efficient Uptake of Angiotensin-Converting Enzyme II Inhibitor Employing Graphene Oxide-Based Magnetic Nanoadsorbents

by Miguel Pereira de Oliveira, Carlos Schnorr, Theodoro da Rosa Salles, Franciele da Silva Bruckmann, Luiza Baumann, Edson Irineu Muller, Wagner Jesus da Silva Garcia, Artur Harres de Oliveira, Luis F. O. Silva and Cristiano Rodrigo Bohn Rhoden

Water 2023, 15(2), 293; https://doi.org/10.3390/w15020293 - 10 Jan 2023

Cited by 7 | Viewed by 1709

Abstract

This paper reports a high efficiency uptake of captopril (CPT), employing magnetic graphene oxide (MGO) as the adsorbent. The graphene oxide (GO) was produced through an oxidation and exfoliation method, and the magnetization technique by the co-precipitation method. The nanomaterials were characterized by [...] Read more.

This paper reports a high efficiency uptake of captopril (CPT), employing magnetic graphene oxide (MGO) as the adsorbent. The graphene oxide (GO) was produced through an oxidation and exfoliation method, and the magnetization technique by the co-precipitation method. The nanomaterials were characterized by FTIR, XRD, SEM, Raman, and VSM analysis. The optimal condition was reached by employing GO·Fe₃O₄ at pH 3.0 (50 mg of adsorbent and 50 mg L⁻¹ of CPT), presenting values of removal percentage and maximum adsorption capacity of 99.43% and 100.41 mg g⁻¹, respectively. The CPT adsorption was dependent on adsorbent dosage, initial concentration of adsorbate, pH, and ionic strength. Sips and Elovich models showed the best adjustment for experimental data, suggesting that adsorption occurs in a heterogeneous surface. Thermodynamic parameters reveal a favorable, exothermic, involving a chemisorption process. The magnetic carbon nanomaterial exhibited a high efficiency after five adsorption/desorption cycles. Finally, the GO·Fe₃O₄ showed an excellent performance in CPT removal, allowing future application in waste management. Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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13 pages, 3296 KiB

Open AccessArticle

Enhanced Removal of Sb (III) by Hydroxy-Iron/Acid–Base-Modified Sepiolite: Surface Structure and Adsorption Mechanism

by Yu Zou, Bozhi Ren, Zhendong He and Xinping Deng

Water 2022, 14(23), 3806; https://doi.org/10.3390/w14233806 - 23 Nov 2022

Cited by 3 | Viewed by 1652

Abstract

To improve the removal of antimony (Sb) from contaminated water, sepiolite (Sep) was chosen as the feedstock, modified with an acid–base and a ferric ion to yield a hydroxy-iron/acid–base-modified sepiolite composite (HI/ABsep). The surface structure of the HI/ABsep and the removal effect of [...] Read more.

To improve the removal of antimony (Sb) from contaminated water, sepiolite (Sep) was chosen as the feedstock, modified with an acid–base and a ferric ion to yield a hydroxy-iron/acid–base-modified sepiolite composite (HI/ABsep). The surface structure of the HI/ABsep and the removal effect of the HI/ABsep on Sb (III) were investigated using potassium tartrate of antimony as the source of antimony and HI/ABsep as the adsorbent. The structural features of the HI/ABsep were analyzed by SEM, FTIR, PXRD, BET, and XPS methods. Static adsorption experiments were performed to investigate the effects of adsorption time, temperature, adsorbent dosage, and pH on the Sb (III) adsorbed by HI/ABsep. This demonstrates that sepiolite has a well-developed pore structure and is an excellent scaffold for the formation of hydroxy-iron. HI/ABsep adsorption of Sb (III) showed the best fit to the pseudo-second-order model and the Freundlich model. The maximum saturated adsorption capacity of the HI/ABsep regarding Sb (III) from Langmuir’s model is 25.67 mg/g at 298 K. Based on the research results, the HI/ABsep has the advantages of easy synthesis and good adsorption performance and has the potential to become a remediation for wastewater contaminated with the heavy metal Sb (III). Full article

(This article belongs to the Special Issue Adsorption Technology for Water and Wastewater Treatments)

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