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Masood, Z.;  Ikhlaq, A.;  Akram, A.;  Qazi, U.Y.;  Rizvi, O.S.;  Javaid, R.;  Alazmi, A.;  Madkour, M.;  Qi, F. Nanocatalysts Used in AOPs for Wastewater Treatment. Encyclopedia. Available online: https://encyclopedia.pub/entry/25412 (accessed on 24 April 2024).
Masood Z,  Ikhlaq A,  Akram A,  Qazi UY,  Rizvi OS,  Javaid R, et al. Nanocatalysts Used in AOPs for Wastewater Treatment. Encyclopedia. Available at: https://encyclopedia.pub/entry/25412. Accessed April 24, 2024.
Masood, Zafar, Amir Ikhlaq, Asia Akram, Umair Yaqub Qazi, Osama Shaheen Rizvi, Rahat Javaid, Amira Alazmi, Metwally Madkour, Fei Qi. "Nanocatalysts Used in AOPs for Wastewater Treatment" Encyclopedia, https://encyclopedia.pub/entry/25412 (accessed April 24, 2024).
Masood, Z.,  Ikhlaq, A.,  Akram, A.,  Qazi, U.Y.,  Rizvi, O.S.,  Javaid, R.,  Alazmi, A.,  Madkour, M., & Qi, F. (2022, July 21). Nanocatalysts Used in AOPs for Wastewater Treatment. In Encyclopedia. https://encyclopedia.pub/entry/25412
Masood, Zafar, et al. "Nanocatalysts Used in AOPs for Wastewater Treatment." Encyclopedia. Web. 21 July, 2022.
Nanocatalysts Used in AOPs for Wastewater Treatment
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This entry is adapted from the peer-reviewed paper 10.3390/catal12070741

The increase in population demands for industrialization and urbanization which led to the introduction of novel hazardous chemicals in our environment. The most significant parts of these harmful substances found in water bodies remain in the background, causing a health risk to humans and animals. It is critical to remove these toxic chemicals from the wastewater to keep a cleaner and greener environment. Hence, wastewater treatment is a challenging area these days to manage liquid wastes effectively. Therefore, scientists are in search of novel technologies to treat and recycle wastewater, and nanotechnology is one of them, thanks to the potential of nanoparticles to effectively clean wastewater while also being ecologically benign. Advanced oxidation processes (AOPs) have been extensively studied. Advanced oxidation processes can be defined as the processes and technologies which involve the generation of active species such as hydroxyl radicals (•OH) which act as efficient oxidants to decompose pollutants in wastewater treatment. 

advanced oxidation processes challenges nanocatalysts

1. Nanocatalysts Used in AOPs for Wastewater Treatment

The nanoparticles possess a high surface area and high density of active site mainly due to their unique size ranging between 1–100 nm [1]. These unique characteristics enable nanomaterials for a variety of applications in wastewater treatment. Various nanomaterials as catalysts were used in the past for such applications; these include metals and their oxides, metal-organic frameworks (MOFs), carbon nanotubes (CNTs), and zeolites, etc. [1]. Nanocatalysts in advanced oxidation processes (AOPs) and their challenges for practical application are shown in Figure 1.
Catalysts 12 00741 g002
Figure 1. Nanocatalysts in AOPs and challenges for practical applications.

2. Graphene-Based Materials

Graphene is an allotropic form of graphite having a systematic honeycomb network. The reduced graphene and its modified forms were used as advanced oxidation catalysts in water and wastewater treatment since reduced graphene oxide (RGO) is less conductive than the parent form [1], and it has been observed that surface hydroxyl groups, Lewis acid sites, and π-electrons play an important role in generating hydroxyl radicals in various AOPs. Moreover, it has a reasonably high surface area and different functional groups (epoxy, carbonyl, hydroxyl) that enable graphene-based catalysts to adsorb pollutants on their surface [1] and efficiently degrade via adsorbed reactive oxygen species (ROS). The multiple pollutants may be a challenge for graphene-based catalysts, as per previous findings, the nature of the pollutant may affect the catalytic ability in AOPs. For example, pollutants may adsorb on the surface of the catalyst and block active sites. Each catalyst type may behave differently for a particular pollutant [2][3][4][5]. RGO-based nanocatalysts were studied in various AOPs to degrade a variety of pollutants. During the photocatalysis reaction, the charge transfer mechanism in the RGO/PEI/Ag nanocatalyst occurred, and the dye molecules moved from the aqueous solution to the composite surface and adsorbed with offset direct orientation via π–π coupling between MB (and RhB) and graphene aromatic sections. When UV was applied on the surface of RGO/PEI/Ag nanocatalyst, the electrons which were photoexcited had a tendency of being rapidly injected into graphene sheets and then reacted with adsorbed oxygen molecules on the surface of graphene to produce O2− or/and O2−2 radicals. In such a way, more electrons and holes could be generated by the prepared composite, and more superoxide anions and/or peroxide species produced, which disintegrated the dyes into the water, carbon dioxide, and other mineralization. As the result of the electron transfer process, recombination of charge was repressed in RGO/PEI/Ag nanocatalyst and consequently, it enhanced the efficacy of the photocatalytic properties [6].
It has been observed that graphene-based catalysts were mostly tested for the treatment of drinking water or synthetic wastewaters by AOPs. However, for large-scale applications, it is crucial to test these catalysts using real wastewater since constituents of real wastewater may affect the overall performance of these catalysts.
Another challenge to applying graphene-based nanocatalysts for water treatment is their organic nature [7]. Since AOPs involve ROS generation that may react with organic-based catalysts to denature them. It is pertinent to mention here that in most of the studies which involve the application of RGO or its modified forms, the loss of catalyst and its reactions with ROS were ignored. On the other hand, some findings indicate that the presence of hydroxyl radical scavengers (such as chlorides) may enhance the activity of RGO [7], which suggested that the catalyst reactivity may reduce in the presence of radical scavengers, and hence its performance may increase. Therefore, it is essential to apply these nanocatalysts using a real wastewater matrix. Table 1 shows examples of research conducted on applying graphene and its modified forms for wastewater treatment by AOPs. In this Table 1, the type of nanocatalysts, wastewater type, and removal efficiencies are addressed. For example, for the removal of methylene blue (MB) dye from the aqueous solution, ZnFe2O4-reduced graphene oxide was applied as a nanocatalyst in the photocatalytic process using H2O2 resulting in 70% MB removal at optimum conditions [8].
Table 1. Graphene and its modified forms as a catalyst used in AOPs for wastewater treatment.
Catalyst Wastewater Type Target Contaminants Removal
Efficiency		 AOPs Reference
RGO Aqueous solution p-hydroxlbenzoic acid (PHBA) TOC removal about 100% in 60 min, at pH 3, PHBA = 20 mg/L Catalytic ozonation [9]
RGO-based silver nanoparticle Aqueous dye solution Methylene blue (MB), rhodamine B (RhB) 100% in 70 min for RhB and 30 min for MB Photocatalytic oxidation [6]
ZnFe2O4-reduced graphene oxide Aqueous dye solution Methylene blue (MB) 70% MB removal Photocatalytic process using H2O2 [8]
N/S-doped graphene derivatives Aqueous solution Oxalic acid 96% in 15 min for photocatalytic ozonation and 20% for catalytic ozonation Catalytic ozonation, photocatalytic ozonation [10]
Hybrid nanocomposites, N-TiO2/graphene/Au, N-TiO2/graphene/Ag Aqueous solution Diazinon 76.7% for N-TiO2/G/Au and 81.1% for N-TiO2/G/Ag were observed at pH = 6 in 60 min Photo-electro catalysis and photo-electro catalytic [11]
ZnO/TiO2 decorated on reduced graphene oxide nanocomposite Real petro-chemical wastewater Phenol Complete degradation of phenol (pH =4), catalyst = 0.6 g/L, Phenol = 60 ppm in 160 min Photocatalytic oxidation [12]
Challenges:
1. Lack of application on real wastewater.
2. Only limited to aqueous solution.
3. Not tested on real wastewater at a large scale.
4. Organic nature can be affected by AOPs.
5. Cost of treatment neither estimated nor compared with other treatment methods.

3. Metals and Metal Oxides

Metals and their oxides were extensively implied as catalysts in both homogeneous and heterogeneous AOPs. It was reported that their surface hydroxyl groups and Lewis acid sites were the main active sites in AOPs [13][14]. Recently various modified forms of metal oxides were tested successfully as nanocatalysts for wastewater treatment. Metal oxide nanoparticles such as ZnO, TiO2, and CeO2 have been widely studied to degrade contaminants in aqueous solutions [15][16][17].
Ye et al. [18] carried out photocatalytic degradation of pharmaceuticals using TiO2 nanotube arrays (TNAs) for the removal of β-blocker metoprolol (MTP) from aqueous solution through free hydroxyl radicals. In order to elaborate on the degradation mechanism, experiments with the addition of specific scavengers were performed. In their study, the maximum contribution of reactive species to MTP degradation was estimated at 88% by free hydroxyl radicals (·OH) in bulk solution, and around 9% by hydroxyl radicals (·OH) and photo-generated holes (h+). Tert-butanol and formic acid were added as a scavenger for ·OH and h+, respectively. A major part of MTP degradation happened due to free hydroxyl radicals whereas minor degradation occurred on the catalysis surface through the reaction of h+ and ·OH adsorbed on the surface of catalysts. Other reactive species such as superoxide radical anions and photo-generated electrons participated in minor degradation of MTP over TNAs of about 3%. Due to their better photocatalytic performance and high surface area, metal oxide nanoparticles are considered better photocatalysts for water purification. Among the metal oxides, iron-based catalysts were extensively studied and were highly effective catalysts for the degradation of various environmental contaminants [15][19]. Iron oxides have advantages of recycling, reusability, and relatively lower usage cost and environmental risks. For example, higher efficiencies were obtained for the degradation of salicylic acid (20 g) using α-Fe2O3 in photocatalyst advanced oxidation process using batch mode [19].
The metals, metal oxides, and their various forms may not exist independently in aqueous environments. In the presence of water molecules, they may hydrate and form different complexes; this process may be pH-dependent [5]. Moreover, the addition of metal oxides and the contaminants present on them may alter the pH of water. Since the AOPs are pH-dependent processes, their mechanism and effectiveness (of various AOPs) depend on water pH [5]. Catalytic ozonation, Fenton-like processes, and UV-based processes are all pH-sensitive processes. For example, the ozonation process requires alkaline pH. Whereas the catalytic hydrogen peroxide decomposition using Fe-based catalysts (Fenton-like process) requires acidic pH to efficiently generate hydroxyl radicals which are necessary for the decomposition of pollutants. For this process, a pH 3 is considered as the optimum and most suitable pH regardless of the target pollutant [20]. At higher pH, Fe3+ forms Fe(OH)3 which decreases the efficiency of the Fenton process, as less Fe3+ is present to react with hydrogen peroxide to generate hydroxyl radicals [20]. On the other hand, a lower pH than 3 causes the formation of Fe complex ([Fe(H2O)6·]2+), which reacts with hydrogen peroxide in the solution, hence lesser hydrogen peroxide is available as an oxidant. In addition, at very low pH, hydrogen peroxide forms stable oxonium ions [H3O2]+, which are stable and less reactive compared to hydroxyl radicals, reducing its efficiency in oxidizing the pollutants [20]. The pH of the water may also affect the nature of active sites and the effectiveness of the catalysts. For example, the point of zero charge is an important property of a material that may determine the surface charges on a material at a particular pH and the nature of active sites (involvement of Lewis and Bronsted acid sites). Therefore, various materials have a characteristic point of zero charge [21][22][23]. Hence, it is indeed important to study the effect of pH on various materials in order to understand their ability to act as a catalyst for wastewater treatment. However, in many published works, the pH changes during the process, and due to contaminants on catalysts, were ignored. Therefore, the mentioned factor should be considered for further application of metals and metal oxides as nanocatalysts in wastewater treatment. Table 2 summarizes various studies applying metal oxides for wastewater treatment by AOPs. For example, Soltani et al. [24] applied sonocatalysis for the removal of chemical oxygen demand (COD) in textile wastewater by using the ZnO nanoparticles (catalyst dosage of 6 mg/L) at 9 pH for 150 min of reaction time resulting in 44% COD removal.
Table 2. Metal oxides in AOPs for wastewater treatment.
Catalyst Wastewater Type Target Contaminants Removal Efficiency AOPs Reference
TiO2 nanotube
arrays (TNAs)		 Aqueous
solution		 β-blocker metoprolol (MTP) 87.09 ± 0.09% in 120 min, pH range = 3–11, nanotube diameter = 53 nm Photocatalytic
degradation		 [18]
Fe2O3
nanoparticles		 Aqueous
solution		 Salicylic acid (SA) 53% of SA Photo-
electrocatalytic process		 [19]
TiO2
nanoparticles		 Petroleum
refinery wastewater		 COD 83% in 120 min, pH = 4, COD = 100 mg/L Photocatalyticoxidation [25]
ZnO
nanoparticles		 Textile wastewater COD 44% in 150 min, pH = 9, catalyst = 6 mg/L Sonocatalysis [24]
CeO2
nanoparticles		 Aqueous dye solution Eriochrome black-T (EBT), Alizarin red S (ARS) 100% in 120 min, dye = 100 mg/L, catalyst = 0.6 g/L Photocatalytic oxidation [26]
Challenges:
1. Metals and metal oxides cannot exist independently.
2. This process is pH dependent.
3. Not tested on real wastewater at a large scale.
4. Cost of treatment neither estimated nor compared with other treatment methods.

4. Zeolites and Modified Zeolites

Zeolites are referred to as a family of aluminosilicate materials that consist of microporous structures [27]. Zeolites were extensively investigated for the removal of contaminants in water and wastewater. Their excellent stability, adsorption, and ion exchange capabilities make them unique from other nanomaterials [28]. Most of the zeolites-based AOPs were used to remove pollutants from aqueous synthetic solutions. However, in many recent investigations, real wastewater samples were used to study the effectiveness of these materials. Ikhlaq et al. [29] used iron-loaded zeolites-A to treat municipal wastewater in catalytic ozonation-based AOP. The results revealed that about 90% reduction in COD values was achieved in 1 h ozonation (O3 = 0.9 mg/min) [30]. Another recent study showed a successful application of zeolite A to treat veterinary pharmaceutical wastewater in a synergic electro-flocculation and catalytic ozonation process [31]. In their study, the COD and turbidity removal efficiencies were compared. Moreover, the removal efficiency of identified pharmaceuticals was also investigated [31].
In most studies, zeolites were employed as support, and the metal nanoparticles were deposited on their surfaces. Most of the published work lacks the investigation of the reuse performance of zeolite-based nanocatalysts [32]. Deposited, doped, or impregnated nanoparticles may leach out in wastewater. Therefore, it is essential to consider their reuse performance and leach out the tendency of metals or metal oxides deposited on various types of zeolites. Table 3 summarizes multiple research applications utilizing zeolites for wastewater treatment. For the removal of pollutant COD from veterinary pharmaceutical wastewater Fe-zeolite A utilized as a catalyst in the synergic electro-flocculation–catalytic ozonation process. When an ozone dose of 0.4 mg/min was provided in a reactor at neutral pH and the Fe-zeolite A dosage was 1.5 g/L, maximum COD removal of 85.12% was achieved [31].
Table 3. Zeolites used as nanocatalysts in AOPs for wastewater treatment.
Catalyst Wastewater Type Target
Contaminants		 Removal Efficiency AOPs Reference
Fe-zeolite A Veterinary pharmaceutical wastewater COD 85.12%, pH = 7,
O3 = 0.4 mg/min, catalyst = 1.5  g/L		 Synergic electro-flocculation–
catalytic ozonation		 [31]
Fe2O3
nanoparticles-
zeolites Y		 Aqueous solution Phenol 90% at neutral pH in 2 h, catalyst = 0.0375 g/mL,
H2O2 = 0.14 mol/L,
phenol = 1.0 g/L		 Fenton-like
process		 [33]
MgO-zeolite
nano-structure		 Textile wastewater COD 61.5%, COD = 2650 mg/L, pH = 6.4, catalyst = 0.7 g/L Sono-
photocatalytic degradation		 [34]
ZnO-HY zeolites Aqueous
solution		 MB 80% in 6 h, catalyst 10 mg/L, pH = 3 Electrochemical [35]
Challenges:
1. May leach out in wastewater.
2. Lack of research in reuse performance.
3. Not tested on real wastewater at a large scale.
4. Cost of treatment neither estimated nor compared with other treatment methods.

5. Carbon Nanotubes

Carbon is a unique and valuable element due to its many allotropes and catenation characteristics. Carbon nanotubes (CNTs) have a large surface area, which allows them to have strong chemical activity and good adsorption properties. CNTs have brought a revolution in the field of water and wastewater treatment. Therefore, these materials should be extensively applied to investigate their effectiveness and utility. CNTs have been studied under various categories such as single-walled or one-dimensional CNTs, multi-walled, and composite CNTs [1]. CNTs have been studied for their ability to remove a variety of contaminants. Many other modified CNTs used to treat various pollutants have been presented in Table 4. CNTs are highly recommended materials in AOPs due to their high removal efficiencies to treat highly resistant pollutants.
Table 4. Carbon nanomaterials and nanotubes as nanocatalysts in AOPs for wastewater treatment.
Catalyst Wastewater Type Target Contaminants Removal
Efficiency		 AOPs References
Multi-walled carbon nanotubes Aqueous solution Atrazine (TOC removal) 80% in 180 min, Co = 10 ppm, mMWCNTs = 100 mg, ozone = 50 g/L Catalytic ozonation [36]
CeO2-carbon nanotubes Aqueous solution Phenol (TOC removal) 96% in 60 min, Phenol = 20 mg/L, catalyst = 0.10 g/L, ozone = 12 mg/L, pH = 6.2 Catalytic ozonation [37]
Fe-CNTs Real wastewater contaminated with dyes TOC removal 40% TOC removal, 5% Fe, catalyst = 200 mg,
H2O2 = 0.4 M		 Fenton-like and photo-Fenton process [38]
CNTs Aqueous solution Nitrobenzene, benzoquinone, phenol 45% benzoquinone and 60% nitrobenzene, in 180 min, 100% phenol in 60 min, Co = 20 mg/L, temperature = 25 °C, catalyst = 0.2 g Peroxy-monosulfate activation [39]
Nitrogen-doped bamboo-like CNTs Aqueous solution Sulfachloro-pyridazine 90% oxidation in 180 min, catalyst = 0.2 g/L, SCP = 20 mg/L, pH = 7 Persulfate activation [40]
Challenges:
1. Not tested on real wastewater at a large scale.
2. Multiple pollutants can be a challenge.
3. Cost of treatment neither estimated nor compared with other treatment methods.
However, most of the studies found in the literature revealed that CNTs were tested in an aqueous environment by using single or multiple pollutants. Only a few studies were conducted using real wastewater to scale up the process using CNTs. Since actual conditions may be more challenging, having multiple contaminants, pollutants, interfering chemicals, and scavengers may affect a catalyst’s performance. Therefore, it is highly required to apply CNTs in real wastewater treatment. Since the real wastewater matrix may affect the ability and effectiveness of a catalyst, the real wastewater is a complex matrix that contained a variety of chemicals that can compete with the reactions of pollutants and oxidants (hydroxyl radicals). For example, carbonates, bicarbonates, phosphates, sulfates, etc., are hydroxyl scavengers. Moreover, the heavy metals and organic acids present in wastewater, if any, may adsorb on the catalyst and may block their active sites. Table 4 summarizes the practical applications of carbon nanomaterials and nanotubes as nanocatalysts in AOPs for wastewater treatment. A study conducted for the removal of TOC from real wastewater contaminated with dyes using Fe-CNTs in the Fenton-like and photo-Fenton process showed a maximum of 40% TOC removal [38].

6. Metal-Organic Frameworks

Metal-organic frameworks (MOFs) are widely utilized as fillers in water purification membranes. These materials are referred to as adsorbents to remove contaminants from the environment [41]. Many researchers focus on their applications as a catalyst in AOPs. Due to their unique properties, such as three-dimensional structures, surface areas, and metal-containing active sites, MOFs have been recently studied in various types of AOP processes (Table 5). Table 5 presents the details of MOFs that have been recently studied in various types of AOP processes. Sun et al. [42] applied catalyzed Fenton process utilizing the Fe(BDC) (DMF,F) as MOFs for the removal of an aromatic compound such as phenol from the solution. It was found that higher removal efficiency of more than 99% was achieved by this treatment process. Although this process is efficient in terms of pollutant removal on a lab scale, there is a need to evaluate the application of this process on real textile wastewater.
Table 5. Metal organic frameworks in AOPs for wastewater treatment.
Catalyst Wastewater Type Target Contaminants Removal Efficiency AOPs References
NF/ZIF-67 Solution Rhodamine B 99% in 30 min Sulfur radical -AOPs [43]
MIL-53(Fe) Matrix solution Methylene blue (MB) 87% in 240 min,
MB = 10 mg/L,
catalyst = 0.4 g/L		 Photocatalytic
process		 [44]
Magnetic
(γ-Fe3O4)		 Matrix solution Methylene blue (MB) 72% in 240 min Photocatalytic
process		 [44]
Fe(BDC) (DMF,F) Solution Phenol High removal efficiency (>99%) Catalyzed Fenton process [42]
STA-12
(Fe, Mn)		 Aqueous solution Rhodamine B and methylene blue (MB) 93% in natural sunlight in 40 min Photo-Fenton oxidation [45]
ZIF-67 Solution Rhodamine B 80% in 60 min
RhB = 50 mg/L, catalyst = 50 mg/L, PMS = 150 mg/L, T = 20 °C		 Sulfate radical (SO4•−) based AOP [46]
Challenges:
1. They themselves leach out.
2. Degraded during processes.
3. Cost of treatment neither estimated nor compared with other treatment methods.
However, the studies on the practical applications of MOFs are limited, and there is a need to test these materials using real wastewater samples. Moreover, it is also essential to investigate the self-degradation of MOFs in the presence of reactive oxygen species (ROS) as MOFs are organic-based materials that might react with radicals produced in AOP systems.

7. Clay-Based Materials

Various researchers investigated the clays due to their availability and economic considerations to promote the production of reactive oxygen species (ROS) to remove multiple pollutants. Among the various AOPs, wet catalytic oxidation and ozone-based catalytic processes were successfully studied to remove pollutants such as phenols and dyes [47][48]. Clays modified with various metals were widely applied to treat wastewater (Table 3). Boudissa et al. [48] suggested that protonated silanol groups (Bronsted acid sites) on clays may play an important role in the production of reactive oxygen species (ROS) while interacting with the dye molecules. Moreover, it was suggested that the charge on the dyes and surface charge on the catalyst might play an important role in the adsorption of various pollutants on the surface of the catalyst that might affect the overall efficiency [48].
Despite several successful published applications of clay-based catalysts in AOPs as summarized in Table 3, they have not been implied on a larger scale for commercial applications. This might be due to the materials’ limitations (recovery of clay waste catalyst and addition of turbidity to wastewater) and a lack of investigations with real wastewaters. The materials’ limitations include a lack of maintaining high porosity and stability, resulting in turbidity to water [49]. Moreover, the leaching of metal nanoparticles deposited to these clay-based supports is very frequently observed during AOPs which also limits their applications in wastewater treatment. These above-stated limitations affect the catalysts’ life and cause the deactivation of the catalysts. Such catalysts are not suitable for long duration processes and cannot be reused [50]. Table 6 summarizes the application of clays as nanocatalysts in AOPs for wastewater treatment. Kalmakhanova et al. [36] applied catalytic ozonation to the degradation of methylene blue, methyl green, methyl orange, and methyl-thymol blue in their aqueous solutions by using an acid-treated clay catalyst. The results showed removal of 49–96% dyes achieved in 20 min of reaction time.
Table 6. Application of clays as nanocatalysts in AOPs for wastewater treatment.
Catalyst Wastewater Type Target
Contaminants		 Removal Efficiency AOPs Reference
Pillared interlayered clay Aqueous solutions/
wastewater		 Phenols >80% Catalytic wet air oxidation, Fenton-like process, photocatalytic treatment [47]
Zr and Fe/Cu/Zr polycations-pillared clay Aqueous solutions 4-nitrophenol 78% TOC removal,
C4-NP = 5 g/L,
CH2O2CH2O2 = 17.8 g/L, catalyst = 2.5 g/L,
pH = 3.0, T = 50 ℃		 Catalytic wet peroxide oxidation [51]
Al/Fe pillared clay Aqueous solutions p-chlorophenol 60% TOC removal Catalytic wet hydrogen peroxide oxidation [52]
Acid-treated clay catalyst Aqueous solutions Methylene blue, methyl green, methyl orange, methyl-thymol blue 49–96% removal in 20 min Catalytic ozonation [48]
Zn-clays catalyst Dye wastewater Dyes >50% COD removal Catalytic ozonation [53]
Challenges:
1. Not tested on real wastewater at large scale.
2. Multiple pollutants can be a challenge.
3. Cost of treatment neither estimated nor compared with other treatment methods.

References

  1. Deshpande, B.D.; Agrawal, P.S.; Yenkie, M.K.N.; Dhoble, S.J. Prospective of Nanotechnology in Degradation of Waste Water: A New Challenges. Nano-Struct. Nano-Objects 2020, 22, 100442.
  2. Ikhlaq, A.; Kasprzyk-Hordern, B. Catalytic Ozonation of Chlorinated VOCs on ZSM-5 Zeolites and Alumina: Formation of Chlorides. Appl. Catal. B Environ. 2017, 200, 274–282.
  3. Ernst, M.; Lurot, F.; Schrotter, J.C. Catalytic Ozonation of Refractory Organic Model Compounds in Aqueous Solution by Aluminum Oxide. Appl. Catal. B Environ. 2004, 47, 15–25.
  4. Nawrocki, J.; Fijołek, L. Catalytic Ozonation-Effect of Carbon Contaminants on the Process of Ozone Decomposition. Appl. Catal. B Environ. 2013, 142–143, 307–314.
  5. Nawrocki, J. Catalytic Ozonation in Water: Controversies and Questions. Discussion Paper. Appl. Catal. B Environ. 2013, 142–143, 465–471.
  6. Jiao, T.; Guo, H.; Zhang, Q.; Peng, Q.; Tang, Y.; Yan, X.; Li, B. Reduced Graphene Oxide-Based Silver Nanoparticle-Containing Composite Hydrogel as Highly Efficient Dye Catalysts for Wastewater Treatment. Sci. Rep. 2015, 5, 11873.
  7. Javaid, R.; Nanba, T. Stability of Cs/Ru/MgO Catalyst for Ammonia Synthesis as a Hydrogen and Energy Carrier. Energies 2022, 15, 3506.
  8. Jumeri, F.A.; Lim, H.N.; Ariffin, S.N.; Huang, N.M.; Teo, P.S.; Fatin, S.O.; Chia, C.H.; Harrison, I. Microwave Synthesis of Magnetically Separable ZnFe2O4-Reduced Graphene Oxide for Wastewater Treatment. Ceram. Int. 2014, 40, 7057–7065.
  9. Wang, Y.; Xie, Y.; Sun, H.; Xiao, J.; Cao, H.; Wang, S. Efficient Catalytic Ozonation over Reduced Graphene Oxide for P-Hydroxylbenzoic Acid (PHBA) Destruction: Active Site and Mechanism. ACS Appl. Mater. Interfaces 2016, 8, 9710–9720.
  10. Pedrosa, M.; Pastrana-Martínez, L.M.; Pereira, M.F.R.; Faria, J.L.; Figueiredo, J.L.; Silva, A.M.T. N/S-Doped Graphene Derivatives and TiO2 for Catalytic Ozonation and Photocatalysis of Water Pollutants. Chem. Eng. J. 2018, 348, 888–897.
  11. Ayoubi-Feiz, B.; Mashhadizadeh, M.H.; Sheydaei, M. Degradation of Diazinon by New Hybrid Nanocomposites N-TiO2/Graphene/Au and N-TiO2/Graphene/Ag Using Visible Light Photo-Electro Catalysis and Photo-Electro Catalytic Ozonation: Optimization and Comparative Study by Taguchi Method. Sep. Purif. Technol. 2019, 211, 704–714.
  12. Hayati, F.; Isari, A.A.; Fattahi, M.; Anvaripour, B.; Jorfi, S. Photocatalytic Decontamination of Phenol and Petrochemical Wastewater through ZnO/TiO2 Decorated on Reduced Graphene Oxide Nanocomposite: Influential Operating Factors, Mechanism, and Electrical Energy Consumption. RSC Adv. 2018, 8, 40035–40053.
  13. Khan, A.H.; Khan, N.A.; Ahmed, S.; Dhingra, A.; Singh, C.P.; Khan, S.U.; Mohammadi, A.A.; Changani, F.; Yousefi, M.; Alam, S. Application of Advanced Oxidation Processes Followed by Different Treatment Technologies for Hospital Wastewater Treatment. J. Clean. Prod. 2020, 269, 122411.
  14. Pocostales, P.; Álvarez, P.; Beltrán, F.J. Catalytic Ozonation Promoted by Alumina-Based Catalysts for the Removal of Some Pharmaceutical Compounds from Water. Chem. Eng. J. 2011, 168, 1289–1295.
  15. Bethi, B.; Sonawane, S.H.; Bhanvase, B.A.; Gumfekar, S.P. Nanomaterials-Based Advanced Oxidation Processes for Wastewater Treatment: A Review. Chem. Eng. Process. Intensif. 2016, 109, 178–189.
  16. Javaid, R.; Tanaka, D.A.P.; Kawanami, H.; Suzuki, T.M. Silica Capillary with Thin Metal (Pd and Pt) Inner Wall: Application to Continuous Decomposition of Hydrogen Peroxide. Chem. Lett. 2009, 38, 146–147.
  17. Javaid, R.; Kawanami, H.; Chatterjee, M.; Ishizaka, T.; Suzuki, A.; Suzuki, T.M. Fabrication of Microtubular Reactors Coated with Thin Catalytic Layer (M=Pd, Pd-Cu, Pt, Rh, Au). Catal. Commun. 2010, 11, 1160–1164.
  18. Ye, Y.; Feng, Y.; Bruning, H.; Yntema, D.; Rijnaarts, H.H.M. Photocatalytic Degradation of Metoprolol by TiO2 Nanotube Arrays and UV-LED: Effects of Catalyst Properties, Operational Parameters, Commonly Present Water Constituents, and Photo-Induced Reactive Species. Appl. Catal. B Environ. 2018, 220, 171–181.
  19. Suryavanshi, R.D.; Mohite, S.V.; Bagade, A.A.; Rajpure, K.Y. Photoelectrocatalytic Activity of Immobilized Fe2O3 Photoelectrode for Degradation of Salicylic Acid and Methyl Orange Dye under Visible Light Illumination. Ionics 2018, 24, 1841–1853.
  20. Buthiyappan, A.; Abdul Aziz, A.R.; Wan Daud, W.M.A. Recent Advances and Prospects of Catalytic Advanced Oxidation Process in Treating Textile Effluents. Rev. Chem. Eng. 2016, 32, 1–47.
  21. Nawrocki, J.; Fijołek, L. Effect of Aluminium Oxide Contaminants on the Process of Ozone Decomposition in Water. Appl. Catal. B Environ. 2013, 142–143, 533–537.
  22. Tian, L.; Nawrocki, W.J.; Liu, X.; Polukhina, I.; Van Stokkum, I.H.M.; Croce, R. PH Dependence, Kinetics and Light-Harvesting Regulation of Nonphotochemical Quenching in Chlamydomonas. Proc. Natl. Acad. Sci. USA 2019, 116, 8320–8325.
  23. Sajjad, S.; Ikhlaq, A.; Javed, F.; Ahmad, S.W.; Qi, F. A Study on the Influence of PH Changes during Catalytic Ozonation Process on Alumina, Zeolites and Activated Carbons for the Decolorization of Reactive Red-241. Water Sci. Technol. 2021, 83, 727–738.
  24. Soltani, R.D.C.; Jorfi, S.; Safari, M.; Rajaei, M.-S. Enhanced Sonocatalysis of Textile Wastewater Using Bentonite-Supported ZnO Nanoparticles: Response Surface Methodological Approach. J. Environ. Manag. 2016, 179, 47–57.
  25. Shahrezaei, F.; Mansouri, Y.; Zinatizadeh, A.A.L.; Akhbari, A. Process Modeling and Kinetic Evaluation of Petroleum Refinery Wastewater Treatment in a Photocatalytic Reactor Using TiO2 Nanoparticles. Powder Technol. 2012, 221, 203–212.
  26. Mishra, S.; Soren, S.; Debnath, A.K.; Aswal, D.K.; Das, N.; Parhi, P. Rapid Microwave—Hydrothermal Synthesis of CeO2 Nanoparticles for Simultaneous Adsorption/Photodegradation of Organic Dyes under Visible Light. Optik 2018, 169, 125–136.
  27. Javaid, R.; Urata, K.; Furukawa, S.; Komatsu, T. Factors Affecting Coke Formation on H-ZSM-5 in Naphtha Cracking. Appl. Catal. A Gen. 2015, 491, 100–105.
  28. Ikhlaq, A.; Javaid, R.; Akram, A.; Qazi, U.Y.; Erfan, J.; Madkour, M.; Abdelbagi, M.E.M.; Shamsah, S.M.I.; Qi, F. Application of Attapulgite Clay-Based Fe-Zeolite 5A in UV- Assisted Catalytic Ozonation for the Removal of Ciprofloxacin. J. Chem. 2022, 2022, 27–30.
  29. Ikhlaq, A.; Fatima, R.; Yaqub Qazi, U.; Javaid, R.; Akram, A.; Shamsah, S.I.; Qi, F.; Todorova, S.; Lebeau, B.; Blin, J.-L.; et al. Combined Iron-Loaded Zeolites and Ozone-Based Process for the Purification of Drinking Water in a Novel Hybrid Reactor: Removal of Faecal Coliforms and Arsenic. Catalysts 2021, 11, 373.
  30. Ikhlaq, A.; Anis, M.; Javed, F.; Ghani, H.; Munir, H.M.S.; Ijaz, K. Catalytic Ozonation for the Treatment of Municipal Wastewater by Iron Loaded Zeolite A. Desalin. Water Treat. 2019, 152, 108–115.
  31. Ikhlaq, A.; Javed, F.; Akram, A.; Rehman, A.; Qi, F.; Javed, M.; Mehdi, M.J.; Waheed, F.; Naveed, S.; Aziz, H.A. Synergic Catalytic Ozonation and Electroflocculation Process for the Treatment of Veterinary Pharmaceutical Wastewater in a Hybrid Reactor. J. Water Process Eng. 2020, 38, 101597.
  32. Gümüş, D.; Akbal, F. Comparison of Fenton and Electro-Fenton Processes for Oxidation of Phenol. Process Saf. Environ. Prot. 2016, 103, 252–258.
  33. Yang, X.; Cheng, X.; Elzatahry, A.A.; Chen, J.; Alghamdi, A.; Deng, Y. Recyclable Fenton-like Catalyst Based on Zeolite Y Supported Ultrafine, Highly-Dispersed Fe2O3 Nanoparticles for Removal of Organics under Mild Conditions. Chin. Chem. Lett. 2019, 30, 324–330.
  34. Jorfi, S.; Pourfadakari, S.; Kakavandi, B. A New Approach in Sono-Photocatalytic Degradation of Recalcitrant Textile Wastewater Using Nanostructure under UVA Irradiation. Chem. Eng. J. 2018, 343, 95–107.
  35. Sapawe, N.; Jalil, A.A.; Triwahyono, S.; Sah, R.N.R.A.; Jusoh, N.W.C.; Hairom, N.H.H.; Efendi, J. Electrochemical Strategy for Grown ZnO Nanoparticles Deposited onto HY Zeolite with Enhanced Photodecolorization of Methylene Blue: Effect of the Formation of SiOZn Bonds. Appl. Catal. A Gen. 2013, 456, 144–158.
  36. Fan, X.; Restivo, J.; Órfão, J.J.M.; Pereira, M.F.R.; Lapkin, A.A. The Role of Multiwalled Carbon Nanotubes (MWCNTs) in the Catalytic Ozonation of Atrazine. Chem. Eng. J. 2014, 241, 66–76.
  37. Wang, J.; Quan, X.; Chen, S.; Yu, H.; Liu, G. Enhanced Catalytic Ozonation by Highly Dispersed CeO2 on Carbon Nanotubes for Mineralization of Organic Pollutants. J. Hazard. Mater. 2019, 368, 621–629.
  38. García, J.C.; Pedroza, A.M.; Daza, C.E. Magnetic Fenton and Photo-Fenton-like Catalysts Supported on Carbon Nanotubes for Wastewater Treatment. Water Air Soil Pollut. 2017, 228, 246.
  39. Duan, X.; Indrawirawan, S.; Kang, J.; Tian, W.; Zhang, H.; Sun, H.; Wang, S. Temperature-Dependent Evolution of Hydroxyl Radicals from Peroxymonosulfate Activation over Nitrogen-Modified Carbon Nanotubes. Sustain. Mater. Technol. 2018, 18, e00082.
  40. Kang, J.; Duan, X.; Wang, C.; Sun, H.; Tan, X.; Tade, M.O.; Wang, S. Nitrogen-Doped Bamboo-like Carbon Nanotubes with Ni Encapsulation for Persulfate Activation to Remove Emerging Contaminants with Excellent Catalytic Stability. Chem. Eng. J. 2018, 332, 398–408.
  41. Priyadarshini, M.; Das, I.; Ghangrekar, M.M. Application of Metal Organic Framework in Wastewater Treatment and Detection of Pollutants: Review. Spec. Issue J. Indian Chem. Soc. 2019, 97, 507–512.
  42. Sun, Q.; Liu, M.; Li, K.; Han, Y.; Zuo, Y.; Wang, J.; Song, C.; Zhang, G.; Guo, X. Controlled Synthesis of Mixed-Valent Fe-Containing Metal Organic Frameworks for the Degradation of Phenol under Mild Conditions. Dalt. Trans. 2016, 45, 7952–7959.
  43. Lin, K.Y.A.; Yang, M.T.; Zhang, Z.Y.; Wi-Afedzi, T.; Lin, Y.F. Prussian Blue Analogue Supported on Sulfur-Doped Carbon Nitride as an Enhanced Heterogeneous Catalyst for Activating Peroxymonosulfate. J. Colloid Interface Sci. 2018, 529, 161–170.
  44. Feng, X.; Chen, H.; Jiang, F. In-Situ Ethylenediamine-Assisted Synthesis of a Magnetic Iron-Based Metal-Organic Framework MIL-53(Fe) for Visible Light Photocatalysis. J. Colloid Interface Sci. 2017, 494, 32–37.
  45. Farrokhi, A.; Feizpour, F.; Asaadzadeh, M. Degradation of Hazardous Organic Dyes with Solar-Driven Advanced Oxidation Process Catalyzed by the Mixed Metal–Organic Frameworks. Appl. Organomet. Chem. 2019, 33, e4928.
  46. Wang, C.; Kim, J.; Malgras, V.; Na, J.; Lin, J.; You, J.; Zhang, M.; Li, J.; Yamauchi, Y. Metal–Organic Frameworks and Their Derived Materials: Emerging Catalysts for a Sulfate Radicals-Based Advanced Oxidation Process in Water Purification. Small 2019, 15, 1900744.
  47. Baloyi, J.; Ntho, T.; Moma, J. Advances Synthesis and Application of Pillared Clay Heterogeneous Catalysts for Wastewater Treatment: A Review. RSC Adv. 2018, 8, 5197–5211.
  48. Boudissa, F.; Mirilà, D.; Arus, V.-A.; Terkmani, T.; Semaan, S.; Proulx, M.; Nistor, I.-D.; Roy, R.; Azzouz, A. Acid-Treated Clay Catalysts for Organic Dye Ozonation—Thorough Mineralization through Optimum Catalyst Basicity and Hydrophilic Character. J. Hazard. Mater. 2019, 364, 356–366.
  49. Rezvani, P.; Taghizadeh, M.M. On Using Clay and Nanoclay Ceramic Granules in Reducing Lead, Arsenic, Nitrate, and Turbidity from Water. Appl. Water Sci. 2018, 8, 1–6.
  50. Herney-Ramirez, J.; Madeira, L.M. Pillared Clays and Related Catalysts; Gil, A., Korili, S.A., Trujillano, R., Vicente, M.A., Eds.; Springer: New York, NY, USA, 2010; ISBN 978-1-4419-6670-4.
  51. Kalmakhanova, M.S.; Diaz de Tuesta, J.L.; Kabykenovna, B.; Gomes, H.T. Pillared Clays from Natural Resources as Catalysts for Catalytic Wet Peroxide Oxidation: Characterization and Kinetic Insights. Environ. Eng. Res. 2020, 25, 186–196.
  52. Catrinescu, C.; Arsene, D.; Teodosiu, C. Catalytic Wet Hydrogen Peroxide Oxidation of Para-Chlorophenol over Al/Fe Pillared Clays (AlFePILCs) Prepared from Different Host Clays. Appl. Catal. B Environ. 2011, 101, 451–460.
  53. Lin, Y.I.N. Characteristics of Zn-Clays Catalysts for Catalytic Ozonation Degrading Process of Dye Wastewater. Geol. J. China Univ. 2000, 6, 260–264.
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Subjects: Engineering, Environmental
Contributors MDPI registered users' name will be linked to their SciProfiles pages. To register with us, please refer to https://encyclopedia.pub/register :
Zafar Masood
,
Amir Ikhlaq
,
Asia Akram
,
Umair Yaqub Qazi
,
Osama Shaheen Rizvi
,
Rahat Javaid
,
Amira Alazmi
,
Metwally Madkour
,
Fei Qi
View Times: 858
Entry Collection: Wastewater Treatment
Revisions: 6 times (View History)
Update Date: 28 Jul 2022
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