1
|
Ortega-Nieto C, Losada-Garcia N, Prodan D, Furtos G, Palomo JM. Recent Advances on the Design and Applications of Antimicrobial Nanomaterials. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2406. [PMID: 37686914 PMCID: PMC10490178 DOI: 10.3390/nano13172406] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023]
Abstract
Present worldwide difficulties in healthcare and the environment have motivated the investigation and research of novel materials in an effort to find novel techniques to address the current challenges and requirements. In particular, the use of nanomaterials has demonstrated a significant promise in the fight against bacterial infections and the problem of antibiotic resistance. Metal nanoparticles and carbon-based nanomaterials in particular have been highlighted for their exceptional abilities to inhibit many types of bacteria and pathogens. In order for these materials to be as effective as possible, synthetic techniques are crucial. Therefore, in this review article, we highlight some recent developments in the design and synthesis of various nanomaterials, including metal nanoparticles (e.g., Ag, Zn, or Cu), metal hybrid nanomaterials, and the synthesis of multi-metallic hybrid nanostructured materials. Following that, examples of these materials' applications in antimicrobial performance targeted at eradicating multi-drug resistant bacteria, material protection such as microbiologically influenced corrosion (MIC), or additives in construction materials have been described.
Collapse
Affiliation(s)
- Clara Ortega-Nieto
- Instituto de Catálisis y Petroleoquímica (ICP), CSIC, c/Marie Curie 2, 28049 Madrid, Spain; (C.O.-N.); (N.L.-G.)
| | - Noelia Losada-Garcia
- Instituto de Catálisis y Petroleoquímica (ICP), CSIC, c/Marie Curie 2, 28049 Madrid, Spain; (C.O.-N.); (N.L.-G.)
| | - Doina Prodan
- Department of Dental Composite Materials, Raluca Ripan Institute of Research in Chemistry, Babes-Bolyai University, 30 Fantanele St., 400294 Cluj-Napoca, Romania;
| | - Gabriel Furtos
- Department of Dental Composite Materials, Raluca Ripan Institute of Research in Chemistry, Babes-Bolyai University, 30 Fantanele St., 400294 Cluj-Napoca, Romania;
| | - Jose M. Palomo
- Instituto de Catálisis y Petroleoquímica (ICP), CSIC, c/Marie Curie 2, 28049 Madrid, Spain; (C.O.-N.); (N.L.-G.)
| |
Collapse
|
2
|
Drabczyk A, Kudłacik-Kramarczyk S, Korniejenko K, Figiela B, Furtos G. Review of Geopolymer Nanocomposites: Novel Materials for Sustainable Development. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16093478. [PMID: 37176360 PMCID: PMC10179758 DOI: 10.3390/ma16093478] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/22/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023]
Abstract
The demand for geopolymer materials is constantly growing. This, in turn, translates into an increasing number of studies aimed at developing new approaches to the methodology of geopolymer synthesis. The range of potential applications of geopolymers can be increased by improving the properties of the components. Future directions of studies on geopolymer materials aim at developing geopolymers showing excellent mechanical properties but also demonstrating significant improvement in thermal, magnetic, or sorption characteristics. Additionally, the current efforts focus not only on the materials' properties but also on obtaining them as a result of environment-friendly approaches performed in line with circular economy assumptions. Scientists look for smart and economical solutions such that a small amount of the modifier will translate into a significant improvement in functional properties. Thus, special attention is paid to the application of nanomaterials. This article presents selected nanoparticles incorporated into geopolymer matrices, including carbon nanotubes, graphene, nanosilica, and titanium dioxide. The review was prepared employing scientific databases, with particular attention given to studies on geopolymer nanocomposites. The purpose of this review article is to discuss geopolymer nanocomposites in the context of a sustainable development approach. Importantly, the main focus is on the influence of these nanomaterials on the physicochemical properties of geopolymer nanocomposites. Such a combination of geopolymer technology and nanotechnology seems to be promising in terms of preparation of nanocomposites with a variety of potential uses.
Collapse
Affiliation(s)
- Anna Drabczyk
- Department of Materials Engineering, Faculty of Materials Engineering and Physics, Cracow University of Technology, 37 Jana Pawła II Av., 31-864 Cracow, Poland
| | - Sonia Kudłacik-Kramarczyk
- Department of Materials Engineering, Faculty of Materials Engineering and Physics, Cracow University of Technology, 37 Jana Pawła II Av., 31-864 Cracow, Poland
| | - Kinga Korniejenko
- Department of Materials Engineering, Faculty of Materials Engineering and Physics, Cracow University of Technology, 37 Jana Pawła II Av., 31-864 Cracow, Poland
| | - Beata Figiela
- Department of Materials Engineering, Faculty of Materials Engineering and Physics, Cracow University of Technology, 37 Jana Pawła II Av., 31-864 Cracow, Poland
| | - Gabriel Furtos
- "Raluca Ripan" Institute for Research in Chemistry, Babes-Bolyai University, 30 Fantanele Street, 400294 Cluj-Napoca, Romania
| |
Collapse
|
3
|
Study on the influence of particle size on the flotation separation of kaolinite and quartz. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
4
|
Gomes BFML, de Araújo CMB, do Nascimento BF, Freire EMPDL, Da Motta Sobrinho MA, Carvalho MN. Synthesis and application of graphene oxide as a nanoadsorbent to remove Cd (II) and Pb (II) from water: adsorption equilibrium, kinetics, and regeneration. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:17358-17372. [PMID: 34664163 DOI: 10.1007/s11356-021-16943-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
In this work, graphene oxide (GO) was synthesized by the modified Hummers method. The nanomaterial was characterized by FTIR and Raman spectroscopy, SEM, and pH at the point of zero charge. GO exhibited typical characteristics of graphene-based materials, indicating that graphite oxidation and exfoliation occurred successfully. Cd (II) and Pb (II) adsorption onto GO was carried out in batch systems, in which the effect of adsorbent dosage, contact time, and initial adsorbate concentration were evaluated. Langmuir, Freundlich, and Sips isotherm models, as well as pseudo order models and Elovich kinetic equation were applied to adsorption experimental data. Results indicated that increasing adsorbent mass, the removal efficiency of Cd (II) and Pb (II) increased. Freundlich isotherm better described Pb (II) adsorption (R2 = 0.96), while Cd (II) isotherm showed linear behavior. From the Akaike's AIC parameter, kinetic data were satisfactorily described by pseudo-first order (Cd (II)) and pseudo-n order (Pb (II)) models. GO was successfully subjected to five regeneration cycles, maintaining high efficiency (> 90%) in all cycles. GO showed high potential for the adsorption of Cd (II) and Pb (II) from aqueous solution, due to its high adsorption capacity, rapid Cd (II) and Pb (II) intakes, and great regeneration performance.
Collapse
Affiliation(s)
- Brener Felipe Melo Lima Gomes
- Department of Rural Technology, Universidade Federal Rural de Pernambuco, R. Dom Manuel de Medeiros, Recife, PE, 52171-900, Brazil.
| | - Caroline Maria Bezerra de Araújo
- Department of Chemical Engineering, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego 1235, Recife, PE, 50670-910, Brazil
| | - Bruna Figueiredo do Nascimento
- Department of Chemical Engineering, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego 1235, Recife, PE, 50670-910, Brazil
| | | | - Mauricio Alves Da Motta Sobrinho
- Department of Chemical Engineering, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego 1235, Recife, PE, 50670-910, Brazil
| | - Marilda Nascimento Carvalho
- Department of Chemical Engineering, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego 1235, Recife, PE, 50670-910, Brazil
| |
Collapse
|
5
|
Kaya-Özkiper K, Uzun A, Soyer-Uzun S. A novel alkali activated magnesium silicate as an effective and mechanically strong adsorbent for methylene blue removal. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127256. [PMID: 34879543 DOI: 10.1016/j.jhazmat.2021.127256] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
A novel, cheap, and easy-to-synthesize sepiolite-based alkali-activated material (Sep-AAM), synthesized by the reaction of a magnesium silicate source, sepiolite, with sodium silicate solution, demonstrating high mechanical strength and methylene blue (MB) removal performance is introduced. Kinetics data indicated that MB adsorption occurs through pseudo-second-order adsorption kinetics model, while the Langmuir isotherm model provided a better fit to adsorption isotherms. The Sep-AAM provided a removal capacity of 99.92 mg g-1 at 50 °C, setting a new benchmark value among the materials used for this purpose. Thermodynamical parameters indicated that the adsorption of MB onto Sep-AAM was endothermic and the interaction between Sep-AAM and MB included weak chemical bonding. Regenerability of the Sep-AAM in powder and monolith forms was confirmed up to four-cycles. Structural parameters determined by several characterization tools demonstrated that the surface hydroxyl groups are responsible for the superior MB adsorption performance. The mechanical strength measurements showed that Sep-AAM in monolith form displayed a remarkable compressive strength value of 40 MPa. To establish a new approach forward on the development of AAMs for wastewater treatment, this study shows that sepiolite can effectively be utilized and Sep-AAM provides a sustainable solution for dye removal with advanced mechanical properties.
Collapse
Affiliation(s)
- Kardelen Kaya-Özkiper
- Department of Chemical Engineering, Bogazici University, Bebek, 34342 Istanbul, Turkey
| | - Alper Uzun
- Department of Chemical and Biological Engineering, Koç University, Rumelifeneri Yolu, Sariyer 34450 Istanbul, Turkey; Koç University TÜPRAŞ Energy Center (KUTEM), Koç University, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey; Koç University Surface Science and Technology Center (KUYTAM), Koç University, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey
| | - Sezen Soyer-Uzun
- Department of Chemical Engineering, Bogazici University, Bebek, 34342 Istanbul, Turkey.
| |
Collapse
|
6
|
High-temperature sulfurized synthesis of MnxCd1−xS/S-kaolin composites for efficient solar-light driven H2 evolution. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2021.127772] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
7
|
Pervaporation Membranes for Seawater Desalination Based on Geo-rGO-TiO 2 Nanocomposites. Part 1: Microstructure Properties. MEMBRANES 2021; 11:membranes11120966. [PMID: 34940467 PMCID: PMC8708729 DOI: 10.3390/membranes11120966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/01/2021] [Accepted: 12/06/2021] [Indexed: 11/24/2022]
Abstract
This is the first of two papers about the synthesis and microstructure properties of the Geo–rGO–TiO2 ternary nanocomposite, which was designed to suit the criteria of a pervaporation membrane for seawater desalination. The performance and capability of Geo–rGO–TiO2 as a seawater desalination pervaporation membrane are described in the second paper. A geopolymer made from alkali-activated metakaolin was utilized as a binder for the rGO-TiO2 nanocomposite. A modified Hummer’s method was used to synthesize graphene oxide (GO), and a hydrothermal procedure on GO produced reduced graphene oxide (rGO). The adopted approach yielded high-quality GO and rGO, based on Raman spectra results. The nanolayered structure of GO and rGO is revealed by Transmission Electron Microscopy (TEM) images. The Geo–rGO–TiO2 ternary nanocomposite was created by dispersing rGO nanosheets and TiO2 nanoparticles into geopolymer paste and stirring it for several minutes. The mixture was then cured in a sealed mold at 70 °C for one hour. After being demolded, the materials were kept for 28 days before being characterized. Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD) measurements revealed that the geopolymer matrix efficiently bonded the rGO and TiO2, creating nanocomposites. Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS) was used to examine the morphology of the outer layer and cross-sections of nanocomposites, and the results displayed that rGO were stacked on the surface as well as in the bulk of the geopolymer and will potentially function as nanochannels with a width of around 0.36 nm, while TiO2 NPs covered the majority of the geopolymer matrix, assisting in anti-biofouling of the membranes. The pores structure of the Geo–rGO–TiO2 were classified as micro–meso pores using the Brunauer–Emmet–Teller (BET) method, indicating that they are appropriate for use as pervaporation membranes. The mechanical strength of the membranes was found to be adequate to withstand high water pressure during the pervaporation process. The addition of rGO and TiO2 NPs was found to improve the hyropobicity of the Geo–rGO–TiO2 nanocomposite, preventing excessive seawater penetration into the membrane during the pervaporation process. The results of this study elucidate that the Geo–rGO–TiO2 nanocomposite has a lot of potential for application as a pervaporation membrane for seawater desalination because all of the initial components are widely available and inexpensive.
Collapse
|
8
|
Noorpour M, Tarighat A. Effects of Si/Al ratio on structure, modulus of elasticity, and density in N-A-S-H geopolymer: a molecular dynamics simulation based on novel macromolecular model. J Mol Model 2021; 27:342. [PMID: 34735610 DOI: 10.1007/s00894-021-04951-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 10/15/2021] [Indexed: 11/28/2022]
Abstract
The Si/Al ratio is of special importance in the structure of geopolymers and its change in structure causes geopolymers to show different properties. This study is based on the proposed macromolecular model taken from recent laboratory studies of the N-A-S-H geopolymer structure and is balanced in terms of electric charge with Na+ ions and aluminum atoms outside the structure. Macromolecular models were made with different ratios of Si/Al equal to 1, 2.16, and 3. Using classical molecular dynamics simulations, the results of Young's modulus, density, and radial distribution function of different Si/Al ratios were compared and the results were in good agreement with the available experimental data. This data is mandatory, please provide.
Collapse
Affiliation(s)
- Mojtaba Noorpour
- Department of Civil Engineering, Shahid Rajaee Teacher Training University, Lavizan, Tehran, 16785-163, Tehran, Iran.
| | - Amir Tarighat
- Department of Civil Engineering, Shahid Rajaee Teacher Training University, Lavizan, Tehran, 16785-163, Tehran, Iran
| |
Collapse
|
9
|
Joshi DJ, Koduru JR, Malek NI, Hussain CM, Kailasa SK. Surface modifications and analytical applications of graphene oxide: A review. Trends Analyt Chem 2021. [DOI: 10.1016/j.trac.2021.116448] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
10
|
Pashaei-Fakhri S, Peighambardoust SJ, Foroutan R, Arsalani N, Ramavandi B. Crystal violet dye sorption over acrylamide/graphene oxide bonded sodium alginate nanocomposite hydrogel. CHEMOSPHERE 2021; 270:129419. [PMID: 33418222 DOI: 10.1016/j.chemosphere.2020.129419] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 12/19/2020] [Accepted: 12/22/2020] [Indexed: 05/07/2023]
Abstract
The synthesis of acrylamide bonded sodium alginate (AM-SA) hydrogel and acrylamide/graphene oxide bonded sodium alginate (AM-GO-SA) nanocomposite hydrogel was successfully performed using the free radical method. The AM-SA and AM-GO-SA hydrogels were applied as composited adsorbents in crystal violet (CV) dye removal. The adsorption process experiments were performed discontinuously and the acquired data showed that the efficiency is more dependent on pH than other factors. The C-O, CO, and CC groups were detected in the produced hydrogels. The amount of surface area was computed to be 44.689 m2/g, 0.0392 m2/g, and 6.983 m2/g for GO, AM-SA, and AM-GO-SA nanocomposite hydrogel, respectively. The results showed that the experimental data follow the Redlich-Peterson isotherm model. Also, the maximum adsorption capacity of monolayer for CV dye adsorption was determined using AM-SA hydrogel and AM-GO-SA nanocomposite hydrogel 62.07 mg/g and 100.30 mg/g, respectively. In addition, the parameters RL, n, and E showed that the processes of adsorption of CV dye using both types of adsorbents are physical and desirable. Thermodynamically, the CV elimination was exothermic and spontaneous. Besides, thermodynamic results showed that the adsorption process is better proceeding at low temperatures. The experimental data followed a pseudo- second- order (PSO) kinetic model. Also, the Elovich model showed that AM-GO-SA nanocomposite hydrogel has more ability to absorb CV dye. Therefore, according to the obtained results, it can be stated that the produced hydrogels are efficient and viable composited adsorbent in removing CV dye from aqueous solution.
Collapse
Affiliation(s)
| | | | - Rauf Foroutan
- Faculty of Chemical & Petroleum Engineering, University of Tabriz, Tabriz, Iran
| | - Nasser Arsalani
- Research Laboratory of Polymer, Department of Organic and Biochemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran
| | - Bahman Ramavandi
- Department of Environmental Health Engineering, Faculty of Health and Nutrition, Bushehr University of Medical Sciences, Bushehr, Iran.
| |
Collapse
|
11
|
Omorogie MO, Babalola JO, Ismaeel MO, McGettrick JD, Watson TM, Dawson DM, Carta M, Kuehnel MF. Activated carbon from Nauclea diderrichii agricultural waste–a promising adsorbent for ibuprofen, methylene blue and CO2. ADV POWDER TECHNOL 2021. [DOI: 10.1016/j.apt.2021.01.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
12
|
Al-Ghouti MA, Khan M, Nasser MS, Al Saad K, Ee Heng OON. Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water. PLoS One 2020; 15:e0239095. [PMID: 33151952 PMCID: PMC7644034 DOI: 10.1371/journal.pone.0239095] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/29/2020] [Indexed: 11/18/2022] Open
Abstract
In this study, municipal solid waste bottom ash (MSW-BA) and fly ash (MSW-FA) were used as a source of aluminosilicate to prepare geopolymer (GEO) adsorbents (GEO-MSWBA and GEO-MSWFA) for the removal of methylene blue (MB) from water. The effects of temperature, pH, and initial concentration on the MB adsorption onto GEO-MSWBA and GEO-MSWFA were evaluated. The adsorption isotherms parameters and thermodynamics were also determined. Detailed physical and chemical characterizations of the prepared adsorbents were carried out to further understand their impact on MB adsorption. The results from the scanning electron microscopy revealed a uniform granule-sphere like structure on both prepared geopolymers, which would facilitate the MB adsorption onto the adsorbents. The X-ray diffraction allowed observation of the microstructural transformations that occur after the alkaline activation. The surface areas of the GEO-MSWBA and the GEO-MSWFA were recorded as 32.78 m2/g and 4.5 m2/g, respectively. From the Fourier transform infrared, a stretching vibration of the aluminosilicate tetrahedral was observed, which indicated the success of geopolymerization. The prepared geopolymers showed a high capability of MB adsorption from an aqueous solution. The adsorption process was best suited and explained using the Langmuir isotherm model with a maximum adsorption capacity of 666.7 mg/g for the GEO-MSWBA (at 25°C) and 769.2 mg/g for the GEO-MSWFA (at 35°C). The positive value of the enthalpy (ΔHo) for the GEO-MSWBA suggested the reaction favored endothermic reaction while the negative value of entropy (ΔSo) indicated a solid/liquid random interaction. On the other hand, the negative ΔHo value for the GEO-MSWFA indicated the reaction followed an exothermic reaction causing energy to be released, the positive ΔSo value indicated a good affinity at the solid-liquid surface. The overall negative value for Gibbs free energy (ΔGo) for both adsorbents suggested the adsorption was spontaneous and feasible. It was also inferred that n- π interaction, direct and indirect hydrogen bond, and electrostatic interaction between the MB and the prepared geopolymers facilitated the adsorption process. The current study shows that the GEO-MSWBA and the GEO-MSWFA have a great potential of removing MB as a cationic dye from water without performing any sort of laborious pretreatments.
Collapse
Affiliation(s)
- Mohammad A. Al-Ghouti
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, Doha, State of Qatar
- * E-mail:
| | - Mariam Khan
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, Doha, State of Qatar
| | - Mustafa S. Nasser
- Gas Processing Center, College of Engineering, Qatar University, Doha, State of Qatar
| | - Khalid Al Saad
- Department of Chemistry and Earth Sciences, College of Arts and Sciences, Qatar University, Doha, State of Qatar
| | - OON Ee Heng
- Domestic Solid Waste Management Centre (DSWMC), Doha, State of Qatar
| |
Collapse
|
13
|
Photocatalytic Nanocomposite Materials Based on Inorganic Polymers (Geopolymers): A Review. Catalysts 2020. [DOI: 10.3390/catal10101158] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Geopolymers are ecologically-friendly inorganic materials which can be produced at low temperatures from industrial wastes such as fly ash, blast furnace slags or mining residues. Although to date their principal applications have been seen as alternatives to Portland cement building materials, their properties make them suitable for a number of more advanced applications, including as photocatalytic nanocomposites for removal of hazardous pollutants from waste water or the atmosphere. For this purpose, they can be combined with photocatalytic moieties such as metal oxides with suitable bandgaps to couple with UV or visible radiation, or with carbon nanotubes or graphene. In these composites the geopolymers act as supports for the photoactive components, but geopolymers formed from wastes containing oxides such as Fe2O3 show intrinsic photoactive behaviour. This review discusses the structure and formation chemistry of geopolymers and the principles required for their utilisation as photocatalysts. The literature on existing photocatalytic geopolymers is reviewed, suggesting that these materials have a promising potential as inexpensive, efficient and ecologically-friendly candidates for the remediation of toxic environmental pollutants and would repay further development.
Collapse
|