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Vlasopoulos D, Mendrinou P, Oustadakis P, Kousi P, Stergiou A, Karamoutsos SD, Hatzikioseyian A, Tsakiridis PE, Remoundaki E, Agatzini-Leonardou S. Hydrometallurgical recovery of silver and gold from waste printed circuit boards and treatment of the wastewater in a biofilm reactor: An integrated pilot application. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 344:118334. [PMID: 37354591 DOI: 10.1016/j.jenvman.2023.118334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/01/2023] [Accepted: 06/04/2023] [Indexed: 06/26/2023]
Abstract
A hydrometallurgical process for the recovery of gold and silver from waste printed circuit boards (PCBs) was experimentally verified and tested at pilot scale. The process comprises four sequential leaching stages; the first two based on HCl, correspond to base metals (e.g. Sn, Cu) removal, while the third is based on HNO3 for Ag leaching and the final on aqua regia for Au leaching. After base metals leaching, the solid residue, enriched in silver and gold about 5 times, contained silver almost quantitively as insoluble AgCl and significant losses (Ag loss <8%) were avoided. The necessary reduction of Ag in the solid phase was achieved with a solution of 0.5 M N2H4 and 3 M NaOH, at 80 °C and S/L ratio 10%. Leaching of silver by 4 M HNO3 was followed by its recovery from nitrate solution by 0.08 Μ N2H4 at ambient temperature with an efficiency of 83%. Gold was leached by aqua regia and quantitively recovered by 0.13 M N2H4 at ambient temperature. Wastewater resulting from the process, rich in nitrate (5 g/L) and chloride (50 g/L), was treated by an effective and novel biological denitrification system tolerating metals at ppm level, to comply with zero nitrate and residual metals discharge guidelines. The overall process requires low reagents and energy input and has zero discharge for liquid effluents. The scheme is appropriate to be applied at local small to medium industrial units, complying with decentralized circular economy principles for metal recovery from electronic waste.
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Affiliation(s)
- Dimitrios Vlasopoulos
- School of Mining and Metallurgical Engineering, National Technical University of Athens (NTUA), Heroon Polytechniou 9, 15780, Zografou, Greece
| | - Panagiota Mendrinou
- School of Mining and Metallurgical Engineering, National Technical University of Athens (NTUA), Heroon Polytechniou 9, 15780, Zografou, Greece
| | - Paschalis Oustadakis
- School of Mining and Metallurgical Engineering, National Technical University of Athens (NTUA), Heroon Polytechniou 9, 15780, Zografou, Greece
| | - Pavlina Kousi
- School of Mining and Metallurgical Engineering, National Technical University of Athens (NTUA), Heroon Polytechniou 9, 15780, Zografou, Greece
| | | | | | - Artin Hatzikioseyian
- School of Mining and Metallurgical Engineering, National Technical University of Athens (NTUA), Heroon Polytechniou 9, 15780, Zografou, Greece
| | - Petros E Tsakiridis
- School of Mining and Metallurgical Engineering, National Technical University of Athens (NTUA), Heroon Polytechniou 9, 15780, Zografou, Greece
| | - Emmanouella Remoundaki
- School of Mining and Metallurgical Engineering, National Technical University of Athens (NTUA), Heroon Polytechniou 9, 15780, Zografou, Greece.
| | - Styliani Agatzini-Leonardou
- School of Mining and Metallurgical Engineering, National Technical University of Athens (NTUA), Heroon Polytechniou 9, 15780, Zografou, Greece
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Alhotan A, Abdelraouf RM, El-Korashy SA, Labban N, Alotaibi H, Matinlinna JP, Hamdy TM. Effect of Adding Silver-Doped Carbon Nanotube Fillers to Heat-Cured Acrylic Denture Base on Impact Strength, Microhardness, and Antimicrobial Activity: A Preliminary Study. Polymers (Basel) 2023; 15:2976. [PMID: 37447621 DOI: 10.3390/polym15132976] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 06/30/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023] Open
Abstract
Poly (methyl methacrylate) (PMMA), is an acrylic polymer substance that is mostly used for denture base applications. The purpose of this laboratory study was to investigate the effect of adding 0.05 wt.% Ag-doped carbon nanotubes (CNT) to PMMA-based (PMMA and MMA) denture base material on the impact strength, microhardness, and antimicrobial activity. A total of 60 heat-cured acrylic resin specimens were prepared. The specimens were randomly divided into two main groups (n = 30/group), according to the powder used: (a) control group, using heat-cured PMMA; (b) treatment group, using a powder prepared by blending 0.05 wt.% silver-doped CNT nanoparticles with heat-cured PMMA. The impact strength, microhardness and anticandidal activity for each group were assessed via the Charpy, Vickers and agar diffusion tests, respectively (n = 10/test for each subgroup). Data were analyzed using independent-sample t-tests (p ≤ 0.05). The results of the impact strength test revealed that the treated heat-cured PMMA-MMA with Ag-doped CNT (2.2 kJ/mm2) was significantly higher than that of the control heat-cured PMMA (1.6 kJ/mm2). Similarly, the Vickers microhardness of the treatment group (52.7 VHN) was significantly higher than that of the control group (19.4 VHN). Regarding the agar diffusion test, after 24 h of incubation, the treated heat-cured PMMA with the Ag-doped CNT exhibited significantly higher anticandidal activity than that of the control group. Therefore, Ag-doped carbon nanotubes could be considered as promising fillers for the dental heat-cured acrylic resin to improve the resistance of the resultant denture against sudden fractures, scratching, and candida invasion.
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Affiliation(s)
- Abdulaziz Alhotan
- Department of Dental Health, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 12372, Saudi Arabia
| | - Rasha M Abdelraouf
- Biomaterials Department, Faculty of Dentistry, Cairo University, Cairo 11553, Egypt
| | - Sabry A El-Korashy
- Department of Chemistry, Faculty of Science, Suez Canal University, Ismailia 41511, Egypt
| | - Nawaf Labban
- Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia
| | - Hanan Alotaibi
- Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia
| | - Jukka P Matinlinna
- Biomaterials Science, Division of Dentistry, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK
| | - Tamer M Hamdy
- Restorative and Dental Materials Department, Oral and Dental Research Institute, National Research Centre (NRC), El Bohouth St., Dokki, Giza 12622, Egypt
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Riaz A, Nosheen S, Mughal TA. Fabrication of biogenic silver nanoparticles from Ficus religiosa bark extract and their application for chromium removal. Microsc Res Tech 2022; 85:3618-3622. [PMID: 35942990 DOI: 10.1002/jemt.24214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 07/06/2022] [Accepted: 07/12/2022] [Indexed: 11/11/2022]
Abstract
Ficus religiosa bark extract was chosen as a reducing agent to fabricate biogenic silver nanoparticles (AgNPs), which were used to treat chromium in synthetic wastewater. The AgNPs formed were characterized using ultraviolet-visible absorption spectroscopy (UV-vis), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results of AgNPs characterization showed that the UV-vis spectrophotometer gave an absorbance peak for AgNPs synthesized from bark extract at 448 nm. The peaks in the XRD pattern of AgNPs synthesized from the bark extract of Ficus religiosa are associated with that of the face-centered-cubic form of metallic silver. The SEM analysis showed clear spherical morphology of AgNPs. These synthesized AgNPs were applied for the removal of chromium from synthetic wastewater. It was seen from the treatment results that above 74.8% removal efficiency was achieved. HIGHLIGHTS: Green synthesis of nanoparticles using plant extracts and their successful application in various fields has been previously studied by various researchers. Ficus religiosa bark extract was used for the synthesis of silver nanoparticles, which after characterization using ultraviolet-visible absorption spectroscopy, scanning electron microscopy, and X-ray diffraction were used to treat chromium in synthetic wastewater prepared in lab. The use of silver nanoparticles for the treatment of heavy metals in wastewater can be considered a good replacement option for the conventional treatment techniques.
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Affiliation(s)
- Aqsa Riaz
- Department of Environmental Science, Lahore College for Women University, Lahore, Pakistan
| | - Sofia Nosheen
- Department of Environmental Science, Lahore College for Women University, Lahore, Pakistan
| | - Tahira Aziz Mughal
- Department of Environmental Science, Lahore College for Women University, Lahore, Pakistan
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Balachandramohan J, Sivasankar T. Sonication-assisted synthesis of a new heterostructured schiff base ligand Silver-Guar gum encapsulated nanocomposite as a visible light photocatalyst. J Microencapsul 2019; 37:29-40. [PMID: 31718349 DOI: 10.1080/02652048.2019.1692944] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A heterostructured Schiff base ligand (Benzildiethylenetriamine)-Silver-Guar gum encapsulated nanocomposites was intended to prepare by simple sonication assisted reflux method. Appropriate composition of purified guar gum, Schiff base ligand and silver nitrate were used for the synthesis. The synthesised nanocomposites were characterised by photoluminescence spectrum, UV-vis diffuse reflectance spectrophotometer, Fourier transform infra-red spectroscopy, X-ray diffractometer, scanning electron microscopy and transmission electron microscopy. The crystalline peaks of XRD and FTIR reveals that Schiff base ligand and guar gum forms metal-organic matrix. Morphology studies have confirmed the organic framework structure and metallic silver nanoparticles are embedded on the organic framework. The efficiency of nanocomposites depends on adsorption capacity and silver nanoparticles that are encapsulated thereby increasing the visible light absorption through surface plasma resonance. The nanocomposite was proved to be highly selective in hydrogenation reaction which favoured the formation of aniline from nitrobenzene as single product with short reaction time and 90% conversion.
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Gharibshahi L, Saion E, Gharibshahi E, Shaari AH, Matori KA. Influence of Poly(vinylpyrrolidone) concentration on properties of silver nanoparticles manufactured by modified thermal treatment method. PLoS One 2017; 12:e0186094. [PMID: 29045414 PMCID: PMC5646761 DOI: 10.1371/journal.pone.0186094] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 09/25/2017] [Indexed: 01/14/2023] Open
Abstract
Very narrow and pure silver nanoparticles were synthesized by modified thermal treatment method via oxygen and nitrogen flow in succession. The structural and optical properties of the calcined silver nanoparticles at 600°C with diverse Poly(vinylpyrrolidone) concentrations varied from 2% to 4% were studied by means of different techniques. Fourier transform infrared spectroscopy was used to monitor the production of pure Ag nanoparticles at a given Poly(vinylpyrrolidone) concentration. The X-ray powder diffraction spectra are evidence for the transformation of the amorphous sample at 30°C to the cubic crystalline nanostructures at the calcination temperatures for all Poly(vinylpyrrolidone) concentrations. The transmission electron microscopy images showed the creation of spherical silver nanoparticles with the average particle size decreased by increasing Poly(vinylpyrrolidone) concentrations from 4.61 nm at 2% to 2.49 nm at 4% Poly(vinylpyrrolidone). The optical properties were investigated by means of UV-vis absorption spectrophotometer, which showed an increase in the conduction band of Ag nanoparticles with increasing Poly(vinylpyrrolidone) concentrations from 2.83 eV at 2% Poly(vinylpyrrolidone) to 2.94 eV at 4% Poly(vinylpyrrolidone) due to decreasing particle size. This was due to less attraction between conduction electrons and metal ions for smaller particle size corresponding to fewer atoms that made up the metal nanoparticles.
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Affiliation(s)
- Leila Gharibshahi
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang, Selangor, Malaysia
| | - Elias Saion
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang, Selangor, Malaysia
| | - Elham Gharibshahi
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang, Selangor, Malaysia
| | - Abdul Halim Shaari
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang, Selangor, Malaysia
| | - Khamirul Amin Matori
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang, Selangor, Malaysia
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Gharibshahi L, Saion E, Gharibshahi E, Shaari AH, Matori KA. Structural and Optical Properties of Ag Nanoparticles Synthesized by Thermal Treatment Method. MATERIALS (BASEL, SWITZERLAND) 2017; 10:E402. [PMID: 28772762 PMCID: PMC5506951 DOI: 10.3390/ma10040402] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 03/12/2017] [Accepted: 03/15/2017] [Indexed: 11/17/2022]
Abstract
The modified thermal treatment method via alternate oxygen and nitrogen flow was successfully employed to synthesize very narrow and pure Ag nanoparticles. The structural and optical properties of the obtained metal nanoparticles at different calcination temperatures between 400 and 800 °C were studied using various techniques. The FTIR and EDX confirmed the formation of Ag nanoparticles without a trace of impurities. The XRD spectra revealed that the amorphous sample at 30 °C had transformed into the cubic crystalline nanostructures at the calcination temperature of 400 °C and higher. The TEM images showed the formation of spherical Ag nanoparticles in which the average particle size decreased with increasing calcination temperature from 7.88 nm at 400 °C to 3.29 nm at 800 °C. The optical properties were determined by UV-vis absorption spectrophotometer, which showed an increase in the conduction band of Ag nanoparticles with increasing calcination temperature from 2.75 eV at 400 °C to 3.04 eV at 800 °C. This was due to less attraction between conduction electrons and metal ions as the particle size decreases in corresponding to fewer numbers of atoms that made up the metal nanoparticles.
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Affiliation(s)
- Leila Gharibshahi
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia.
| | - Elias Saion
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia.
| | - Elham Gharibshahi
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia.
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA.
| | - Abdul Halim Shaari
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia.
| | - Khamirul Amin Matori
- Department of Physics, Faculty of Science, University of Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia.
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Mameneh R, Ghaffari-Moghaddam M, Solouki M, Samzadeh-Kermani A, Sharifmoghadam MR. Characterization and antibacterial activity of plant mediated silver nanoparticles biosynthesized using Scrophularia striata flower extract. RUSS J APPL CHEM+ 2015. [DOI: 10.1134/s1070427215030271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ghaffari-Moghaddam M, Hadi-Dabanlou R, Khajeh M, Rakhshanipour M, Shameli K. Green synthesis of silver nanoparticles using plant extracts. KOREAN J CHEM ENG 2014. [DOI: 10.1007/s11814-014-0014-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Mohan Kumar K, Sinha M, Mandal BK, Ghosh AR, Siva Kumar K, Sreedhara Reddy P. Green synthesis of silver nanoparticles using Terminalia chebula extract at room temperature and their antimicrobial studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 91:228-233. [PMID: 22381795 DOI: 10.1016/j.saa.2012.02.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 01/25/2012] [Accepted: 02/02/2012] [Indexed: 05/31/2023]
Abstract
A green rapid biogenic synthesis of silver nanoparticles (Ag NPs) using Terminalia chebula (T. chebula) aqueous extract was demonstrated in this present study. The formation of silver nanoparticles was confirmed by Surface Plasmon Resonance (SPR) at 452 nm using UV-visible spectrophotometer. The reduction of silver ions to silver nanoparticles by T. chebula extract was completed within 20 min which was evidenced potentiometrically. Synthesised nanoparticles were characterised using UV-vis spectroscopy, Fourier transformed infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The hydrolysable tannins such as di/tri-galloyl-glucose present in the extract were hydrolyzed to gallic acid and glucose that served as reductant while oxidised polyphenols acted as stabilizers. In addition, it showed good antimicrobial activity towards both Gram-positive bacteria (S. aureus ATCC 25923) and Gram-negative bacteria (E. coli ATCC 25922). Industrially it may be a smart option for the preparation of silver nanoparticles.
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Affiliation(s)
- Kesarla Mohan Kumar
- Trace Elements Speciation Research Laboratory, Environmental and Analytical Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, India
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