Article
Engineering, Chemical
Zhan Ding, Yunxiao Bi, Jie Li, Jiaqiao Yuan, Huixin Dai, Shaojun Bai
Summary: The selective flotation separation of chalcopyrite and pyrite was achieved using Fenton oxidation modification in a low alkaline acid mine drainage (AMD) system. The micro-flotation experiment showed a maximum recovery difference of 74.6% between chalcopyrite and pyrite under recommended test conditions. Various analyses confirmed that the hydrophilic species caused by Fenton oxidation hindered the interaction between pyrite surfaces and EX collector, while having a weak influence on the floatability of chalcopyrite.
MINERALS ENGINEERING
(2022)
Article
Environmental Sciences
Qian Guo, Wenjie Zhu, Daoli Yang, Xi Wang, Yinghao Li, Chao Gong, Jiali Yan, Jinli Zhai, Xiaoya Gao, Yongming Luo
Summary: In this study, a green solar photo-Fenton system based on natural pyrite was developed for the efficient degradation of carbamazepine. The system utilized natural organic acids to promote in-situ production of H2O2 and Fe(II) species, ensuring an efficient Fenton reaction without the need for additional H2O2 and pH adjustment. The system demonstrated a significant enhancement in the degradation efficiency of carbamazepine compared to pure pyrite, showcasing the potential of natural pyrite for environmental remediation.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Engineering, Chemical
Wanjia Zhang, Xu Jiang, John Ralston, Jian Cao, Xin Jin, Wei Sun, Zhiyong Gao
Summary: Eosin Y, a commonly used dye for cotton and silk, is highly toxic and difficult to degrade. Around 20% of it becomes organic dye wastewater during the printing and dyeing process, posing serious harm to the environment and human health. In this study, naturally oxidized pyrite was chosen as a promising photocatalyst to degrade Eosin Y, achieving over 90% degradation under specific conditions.
MINERALS ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Fengling Zhang, Jianxing Liu, Hongrui Yue, Gongjin Cheng, Xiangxin Xue
Summary: Pyrite exhibited excellent catalytic activity in the Photo-Fenton process for rapid degradation of methylene blue. Pyrite nanoparticles synthesized via a one-step solvothermal method on graphene sheets showed higher photocatalytic activity and cycling stability.
Article
Engineering, Chemical
Xu Yang, Yubiao Li, Rong Fan, Wanqing Duan, Lingyun Huang, Qing Xiao
Summary: The study found that H2O2 can effectively oxidize pyrite in seawater, making it easier to separate from chalcopyrite. Under optimized conditions, a recovery difference of over 70% was achieved. Additionally, H2O2 reduces the hydrophilicity of the pyrite surface, making it more difficult for collectors to adsorb.
MINERALS ENGINEERING
(2022)
Article
Biochemistry & Molecular Biology
Juntao Guo, Yihui Zhang, Jinjun Li, Feng Wu, Liting Luo
Summary: This study developed a pyrite-based photo-Fenton system using citric acid and simulated/natural sunlight, which could generate H2O2 in situ through enhanced activation of molecular oxygen, for the degradation of pollutants. The system showed high efficiency in degrading acetaminophen under both xenon lamp and natural sunlight irradiation.
Article
Environmental Sciences
Chao Gong, Jinli Zhai, Xi Wang, Wenjie Zhu, Daoli Yang, Yongming Luo, Xiaoya Gao
Summary: In this study, a heterogeneous photo-Fenton and photo-catalytic system was constructed using oxide pyrite (FeS2/Fe2O3) mineral and organic acids. The system enhanced the degradation efficiency of carbamazepine (CBZ) through the synergistic photo-Fenton and photo-catalytic reaction. This investigation provides an innovative strategy for the removal of organic pollutants using natural minerals.
Article
Engineering, Environmental
Bruno M. Esteves, Sergio Morales-Torres, Francisco J. Maldonado-Hodar, Luis M. Madeira
Summary: Iron oxide catalysts supported on activated carbon prepared from olive stones show high efficiency in the degradation of refractory polyphenolic solutions and olive mill wastewater, achieving high removal and mineralization rates, and reducing the eco-toxicity of the wastewater.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Engineering, Chemical
Guang Han, Shuming Wen, Han Wang, Qicheng Feng, Xu Bai
Summary: Pyrogallic acid can effectively reduce the flotation recovery of pyrite, while slightly affecting chalcopyrite. It interacts with the pyrite surface through chemical adsorption, increasing the hydrophilicity of pyrite particles, making it a promising depressant for pyrite in flotation separation.
SEPARATION AND PURIFICATION TECHNOLOGY
(2021)
Article
Chemistry, Physical
Ivan Valles, Ivan Sciscenko, Margarita Mora, Pau Mico, Ana M. Amat, Lucas Santos-Juanes, Javier Moreno-Andres, Antonio Arques
Summary: In this study, the effect of Fe(III) complexation by phenolic derivatives on photo-Fenton was systematically investigated. Solutions containing a mixture of six pollutants were treated by solar simulated photo-Fenton under specific conditions. It was found that the efficiency of ligands increased with the presence of -OH groups, but decreased with the presence of -COOH and -OCH3 groups, which was correlated with the ability of ligands to reduce Fe(III) to Fe(II).
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Chemistry, Physical
Dharmendr Kumar, Sriram Goverapet Srinivasan, Vinay Jain, Beena Rai
Summary: Density functional theory calculations show that thione tautomer of 2-mercaptobenzothiazole adsorbs more strongly on pyrite and chalcopyrite surfaces, leading to enhanced efficiency in selective recognition and separation of target minerals.
APPLIED SURFACE SCIENCE
(2022)
Article
Engineering, Chemical
Richard Li Jie Lee, Xumeng Chen, Yongjun Peng
Summary: This study investigated the effect of pyrite proportion on chalcopyrite and pyrite flotation and found that the introduction of pyrite decreased Cu grade and Cu recovery, but Cu recovery could be restored with a higher pyrite proportion. Electrochemical studies revealed that the galvanic interaction between chalcopyrite and pyrite played a role in controlling flotation behaviors by affecting chalcopyrite oxidation and copper activation on pyrite.
MINERALS ENGINEERING
(2022)
Article
Engineering, Chemical
Huiqi Duan, Xiaoping Huang, Xiaoyu Cao, Zhanfang Cao, Hong Zhong, Jianxian Zeng, Hu Zhou, Jianrong Xue, Yuan Liu
Summary: A novel surfactant BDETU with C=O and C=S groups exhibits strong collecting ability and excellent selectivity for chalcopyrite against pyrite, attributed to the selectively adsorption on chalcopyrite surface and formation of chemical adsorption structures. The adsorption mechanism reveals the interaction between BDETU and copper species on chalcopyrite surface.
MINERALS ENGINEERING
(2021)
Article
Metallurgy & Metallurgical Engineering
Michael J. Nicol
Summary: This detailed electrochemical study defines the role of galvanic coupling between chalcopyrite and pyrite in enhancing the dissolution rate of chalcopyrite in acidic sulfate and chloride solutions at 30 degrees C. The study shows that the galvanic contact with pyrite only marginally increases the dissolution rate of chalcopyrite, regardless of the presence of iron(III) in both sulfate and chloride solutions. The effect of potential on the anodic oxidation rate of chalcopyrite is small under these conditions. Copper(II) as an oxidant in chloride solutions leads to small galvanic currents due to the lower reduction potential of the copper(II)/copper(I) couple. Additionally, the galvanic currents with dissolved oxygen as an oxidant are significantly lower than with iron(III) as an oxidant, indicating that oxygen is less effective than iron(III) in oxidizing chalcopyrite even when coupled with pyrite. The small galvanic currents observed in this study cannot account for the relatively large increases in dissolution rate previously observed in agitated leaching of chalcopyrite/pyrite slurries at elevated temperatures.
Article
Engineering, Chemical
Jinpeng Cai, Xiaodong Jia, Yinyu Ma, Bin Pei, Ayman M. Ibrahim, Chao Su, Peilun Shen, Dianwen Liu
Summary: This study investigated the suitability of sodium polyacrylate as a pyrite depressant in a Cu-S separation system and found that it effectively separated chalcopyrite from pyrite through flotation and adsorption experiments.
MINERALS ENGINEERING
(2022)
Article
Chemistry, Applied
Andre Torres-Pinto, Claudia G. Silva, Joaquim L. Faria, Adrian M. T. Silva
Summary: There is a strong demand to identify sustainable methods for producing nanostructured materials, particularly carbon nitride photocatalysts. This study evaluated the impact of different precursors on the microwave synthesis of these materials and their photocatalytic performances. The photocatalyst prepared with the urea precursor after a two-step microwave treatment showed the best performance for phenol degradation and total organic carbon removal.
Article
Chemistry, Applied
Fernanda F. Roman, Jose L. Diaz de Tuesta, Flavia K. K. Sanches, Adriano Santos Silva, Pricila Marin, Bruno F. Machado, Philippe Serp, Marta Pedrosa, Adrian M. T. Silva, Joaquim L. Faria, Helder T. Gomes
Summary: The intense industrial development has caused an increase in the discharge of oily products in water bodies, which has negative impacts on human and environmental health. Finding alternatives to treat oily wastewater and recover valuable products is important. In this study, Janus-like carbon nanotubes were synthesized and tested as catalysts for treating 4-nitrophenol in simulated oily wastewater.
Article
Biochemistry & Molecular Biology
Marta O. O. Barbosa, Nuno Ratola, Vera Homem, M. Fernando R. Pereira, Adrian M. T. Silva, Ana R. L. Ribeiro, Marta Llorca, Marinella Farre
Summary: Eighteen PFASs were studied in surface waters of four river basins in Portugal. All sampling sites showed contamination in at least one season. The most frequent PFASs varied between dry and wet seasons. PFOS and PFOA were the most frequent in dry season, while PFOA and PFBS were the most frequent in wet season. The potential environmental risks of PFASs were evaluated based on risk quotient (RQ), showing generally low risk except for PFTeA which posed high risks for fish and daphnids.
Article
Chemistry, Multidisciplinary
Andre Torres-Pinto, Hanane Boumeriame, Claudia G. Silva, Joaquim L. Faria, Adrian M. T. Silva
Summary: In this study, thermally exfoliated carbon nitride (CN) was functionalized for the first time via a hydrothermal route using glucose, perylene, and anthraquinone as functionalization agents. The functionalized photocatalysts showed improved rates of hydrogen peroxide (H2O2) production in aqueous solutions, indicating enhanced energy transfer and faster redox reactions. Surface chemistry analysis and optical/electrochemical characterizations confirmed reduced recombination of charge carriers and thermodynamically favored H2O2 generation for the functionalized materials.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Applied
Laura Valenzuela, Marta Pedrosa, Ana Bahamonde, Roberto Rosal, Andre Torres-Pinto, Claudia G. Silva, Joaquim L. Faria, Adrian M. T. Silva
Summary: In this study, metal-free carbon nitride-based membranes were successfully prepared by incorporating bulk or exfoliated graphitic carbon nitride (g-C3N4) photocatalysts into a polyvinylidene fluoride (PVDF) matrix. Supported membranes were also made by immobilizing these photocatalysts on a polytetrafluoroethylene (PTFE) substrate. The membranes exhibited efficient photocatalytic filtration performance for venlafaxine (VFX) degradation under visible light irradiation, with conversions above 95% and negligible VFX concentration in the effluent after 5 hours of operation. Furthermore, the membranes showed resistance to fouling and maintained a constant permeate flux throughout continuous operation.
Article
Engineering, Environmental
Maria J. Sampaio, Ana R. L. Ribeiro, Claudia M. R. Ribeiro, Rita A. Borges, Marta F. Pedrosa, Adrian M. T. Silva, Claudia G. Silva, Joaquim L. Faria
Summary: The presence of micropollutants in water poses a significant risk to ecosystems and human health. A metal-free photocatalyst immobilized in the form of a film was successfully used to degrade pharmaceutical compounds in both laboratory batch and continuous flow reactors. The photocatalytic system also demonstrated efficient removal of other micropollutants in complex wastewater matrices and reduced the toxicity of the wastewater samples, as observed in ecotoxicity tests using Daphnia magna.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Teresa I. A. Gouveia, Adrian M. T. Silva, Mara G. Freire, Ana C. A. Sousa, Arminda Alves, Monica S. F. Santos
Summary: The presence and temporal evolution of cytostatics in wastewaters from a Portuguese hospital center were evaluated. A total of 129 samples were collected over a 9-month period. The study focused on 11 out of 13 pharmaceuticals, including previously unmonitored drugs like flutamide, mycophenolate mofetil, and mycophenolic acid. The results showed that all pharmaceuticals were detected in at least one sample, with bicalutamide and mycophenolic acid being the most frequently detected and concentrated compounds. Etoposide, classified as carcinogenic to humans, was also found in a significant number of samples.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Chemistry, Physical
Maria A. Barros, Catarina L. Seabra, Maria J. Sampaio, Claudia Nunes, Claudia G. Silva, Salette Reis, Joaquim L. Faria
Summary: A metal-free graphitic carbon nitride (GCN-T) photocatalyst was immobilised on cotton fabrics using a microwave-assisted technique. Coated-cotton with 0.81% GCN-T showed effective antimicrobial properties, eradicating pathogenic bacteria like P. aeruginosa and E. coli after 60 minutes of visible light irradiation. The coated cotton also exhibited self-cleaning activity for the degradation of Rhodamine B stains after 60 minutes of LED irradiation.
APPLIED SURFACE SCIENCE
(2023)
Article
Environmental Sciences
Andre Torres-Pinto, Inmaculada Velo-Gala, Sara Ribeirinho-Soares, Olga C. Nunes, Claudia G. Silva, Joaquim L. Faria, Adrian M. T. Silva
Summary: Graphitic carbon nitride (GCN) is a promising optical semiconductor with excellent photoactivity under visible light irradiation. This study successfully improved the photocatalytic and electrocatalytic activities of GCN through thermal and chemical modification, leading to efficient organic micropollutant removal and microorganism inactivation in contaminated water.
ENVIRONMENTAL RESEARCH
(2023)
Article
Chemistry, Physical
Fernanda F. Roman, Larissa De Grande Piccinin, Adriano Santos Silva, Jose L. Diaz de Tuesta, Isabella V. K. Freitas, Admilson Vieira, Giane Goncalves Lenzi, Adrian Manuel Tavares Silva, Joaquim Luis Faria, Helder Teixeira Gomes
Summary: This study explores the preparation of carbon nanotubes (CNTs) using polyolefin plastic solid waste (PSW) and their application as catalysts for catalytic wet peroxide oxidation (CWPO) in the degradation of quinoline (QN). The results demonstrate that carbon nanotubes derived from polyolefins are effective catalysts in the CWPO process for quinoline abatement.
Article
Chemistry, Multidisciplinary
Simone Moretto, Adriano Santos Silva, Jose L. Diaz de Tuesta, Fernanda F. Roman, Rita Cortesi, Ana Raquel Bertao, Manuel Banobre-Lopez, Marta Pedrosa, Adrian M. T. Silva, Helder T. Gomes
Summary: This study explores nickel ferrite nanoparticles as a magnetic core for drug delivery systems. The developed nanoparticles possess stability, biocompatibility, and suitable size for biomedical applications. The nanoparticles demonstrate versatility in drug loading and pH-triggered release under acidic conditions.
MATERIALS TODAY CHEMISTRY
(2023)
Article
Engineering, Environmental
Adrian Mari, Jose Alberto Baeza, Marta Pedrosa, O. Salome G. P. Soares, Luisa Calvo, Miguel Angel Gilarranz, Adrian M. T. Silva, M. Fernando R. Pereira
Summary: In this study, powdered Pd and Pd-Cu catalysts supported on carbon materials with different structural properties were used to prepare catalytic membranes for the reduction of oxoanions in drinking water. The Pd catalytic membranes showed high activity in the reduction of NO2- and BrO3-, while the Pd-Cu catalytic membranes exhibited higher selectivity to NH4+ in the reduction of NO3-. The use of a flow-through configuration reactor facilitated the control of H2 transfer and availability, allowing for the tuning of conditions for both activity and selectivity.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Engineering, Environmental
Joana Abreu-Silva, Sara Ribeirinho-Soares, Ines Oliveira-Inocencio, Marta Pedrosa, Adrian M. T. Silva, Olga C. Nunes, Celia M. Manaia
Summary: This study investigated the performance of three types of filtering membranes (PC, CN, and PES) for bacterial analysis in demineralized and disinfected waters. CN or PES membranes required shorter filtration periods compared to PC membranes, although they had slightly lower DNA extraction yields. However, there were no significant differences in the abundance of genes per volume of water. CN membranes are a cost-effective alternative for analyzing waters with low microbial loads.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Chemistry, Physical
Hanane Boumeriame, Alexey Cherevan, Dominik Eder, Dogukan H. Apaydin, Tarik Chafik, Eliana S. Da Silva, Joaquim L. Faria
Summary: In this study, CuAl layered double hydroxide (LDH) and polymeric carbon nitride (g-C3N4, GCNN) were assembled into novel 2D/2D CuAl-LDH/GCNN heterostructures for visible-light-driven water splitting. The heterostructures exhibited significantly enhanced H-2 evolution, with the optimal LDH loading of 0.2CuAl-LDH/GCNN showing a 32-fold increase compared to GCNN. Additionally, 0.2CuAl-LDH/GCNN generated 1.5 times more O-2 than GCNN. The improved photocatalytic performance was attributed to efficient charge separation at the heterojunction interface, enhanced utilization of longer-wavelength photons, and higher surface area for catalytic reactions.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)