Monitoring of municipal waste streams and their transformation into geopolymers

Funder

Organizational Unit

Publications

Hybrid multi-core shell magnetic nanoparticles for wet peroxide oxidation of paracetamol: application in synthetic and real matrices

Publication . Silva, Adriano S.; Roman, Fernanda; Dias, Arnaldo; Díaz de Tuesta, Jose Luis; Narcizo, Alexandre; Silva, Ana P. F.; Çaha, Ihsan; Deepak, Francis Leonard; Bañobre-López, Manuel; Ferrari, Ana M.; Gomes, Helder

Clean water availability is becoming a matter of global concern in the last decades. The responsible entities for wastewater treatment do not have the proper facilities to deal with a wide range of pollutants. Special attention should be given to emerging contaminants, whose presence in water bodies may cause adverse effects on the aquatic ecosystem and human health. Most studies in the literature do not consider the development of their solution in real matrices, which can hinder the applicability of the explored alternative in the real scenario. Therefore, in this work, we demonstrate the applicability of hybrid magnetic nanoparticles for removing paracetamol (PCM) from simulated and real matrices by catalytic wet peroxide oxidation (CWPO). To achieve carbon coating, the nanoparticles were prepared via the traditional route (resorcinol/formaldehyde, CoFe@CRF). A new methodology was also considered for synthesizing thin-layered carbon-coated magnetic nanoparticles (phloroglucinol/ glyoxalic acid, CoFe@CPG). TEM images revealed a multi-core shell structure formation, with an average carbon layer size of 7.8 ± 0.5 and 3.2 ± 0.3 nm for resorcinol/formaldehyde and phloroglucinol/ glyoxalic acid methodology, respectively. Screening the materials’ activity for PCM oxidation by CWPO revealed that the nanoparticle prepared by phloroglucinol/glyoxalic acid methodology has higher performance for the degradation of PCM, achieving 63.5% mineralization after 24 h of reaction, with similar results for more complex matrices. Iron leaching measured at the end of all reactions has proven that the carbon layer protects the core against leaching.

2023Journal article

Open access

Carbon-Coated Magnetic Catalysts for Enhanced Degradation of Nitrophenols: Stability and Efficiency in Catalytic Wet Peroxide Oxidation

Publication . Baldo, Arthur P.; Bezerra, Ana J.B.; Silva, Adriano S.; Silva, Ana P. F.; Roman, Fernanda; Çaha, Ihsan; Bañobre-López, Manuel; Deepak, Francis Leonard; Gomes, Helder

Nitrophenols are persistent organic pollutants that pose serious environmental and health risks due to their toxic and lipophilic nature. Their persistence arises from strong aromatic stability and resistance to biodegradation, while their lipophilicity facilitates bioaccumulation, exacerbating ecological and human health concerns. To address this challenge, this study focuses on the synthesis and characterization of two different types of hybrid multi-core magnetic catalysts: (i) cobalt ferrite (Co-Fe2O4), which exhibits ferrimagnetic properties, and (ii) magnetite (Fe3O4), which demonstrates close superparamagnetic behavior and is coated with a novel and less hazardous phloroglucinol–glyoxal-derived resin. This approach aims to enhance catalytic efficiency while reducing the environmental impact, offering a sustainable solution for the degradation of nitrophenols in aqueous matrices. Transmission electron microscopy (TEM) images revealed the formation of a multi-core shell structure, with carbon layer sizes of 6.6 ± 0.7 nm for cobalt ferrite and 4.2 ± 0.2 nm for magnetite. The catalysts were designed to enhance the stability and performance in catalytic wet peroxide oxidation (CWPO) processes using sol–gel and solution combustion synthesis methods, respectively. In experiments of single-component degradation, the carbon-coated cobalt ferrite (CoFe@C) catalyst achieved 90% removal of 2-nitrophenol (2-NP) and 96% of 4-nitrophenol (4-NP), while carbon-coated magnetite (Fe3O4@C) demonstrated similar efficiency, with 86% removal of 2-NP and 94% of 4-NP. In the multi-component system, CoFe@C exhibited the highest catalytic activity, reaching 96% removal of 2-NP, 99% of 4-NP, and 91% decomposition of H2O2. No leaching of iron was detected in the coated catalysts, whereas the uncoated materials exhibited similar and significant leaching (CoFe: 5.66 mg/L, Fe3O4: 12 mg/L) in the single- and multi-component system. This study underscores the potential of hybrid magnetic catalysts for sustainable environmental remediation, demonstrating a dual-function mechanism that enhances catalytic activity and structural stability.

2025Journal article

Open access

Enhancing single and multi-component adsorption efficiency of pharmaceutical emerging contaminants using bio waste-derived carbon materials and geopolymers

Publication . Silva, Ana P. F.; Baldo, Arthur P.; Silva, Adriano S.; Natal, Ana Paula S.; Bezerra, Ana J.B.; Tuesta, Jose L. Diaz de; Marin, Pricila; Peres, José A.; Gomes, Helder

Water contamination with pharmaceuticals like acetaminophen (ACT), sulfamethoxazole (SMX), and phenolic compounds such as gallic acid (GA), have become a global concern. These contaminants are persistent environmental pollutants that threaten aquatic life and human health. Adsorption is recognized as an efficient and low-cost solution to tackle water pollution. In this study, the efficiency of three adsorbents—activated carbon (AC), geopolymer (GP), and carbon nanotubes (CNT) prepared from solid wastes for the removal of ACT, SMX, and GA by adsorption is assessed. AC, GP and CNT are synthesized from real wastes to address solid waste management needs. Physisorption confirmed AC superior BET surface area (527 m2 g 1), followed by CNTs (66 m2 g 1) and GPs (30 m2 g 1), allowing to achieve the highest adsorption capacity: 126.8 mg g 1 for ACT, 54.9 mg g 1 for SMX, and 151.5 mg g 1 for GA, with respective breakthrough times of 314, 66, and 68 min. Kinetic and isotherm adsorption models are fitted for all pair pollutant-adsorbent reaching 33 equations to accurately predict adsorption process, concluding that pseudo-second-order kinetic and Freundlich model best fit experimental data, demonstrating a strong adsorbent-adsorbate affinity. The findings suggest that these sustainable materials offer promising solutions for treating contaminated water.

2025Journal article

Embargoed access

Growth of Carbon Nanotubes on Co(x)‐Ni(1‐x) Ferrites by Chemical Vapor Deposition and Performance on Catalytic Wet Peroxide Oxidation

Publication . Silva, Adriano S.; Roman, Fernanda; Díaz de Tuesta, Jose Luis; Olias, Lola G.; Çaha, Ihsan; Ferreira, Ana P.; Souza, Renata P. de; Deepak, Francis Leonard; Pereira, Ana I.; Silva, Adrián M. T.; Gomes, Helder

Upcycling plastic solid wastes (PSWs) into high-value carbon nanotubes (CNTs) offers a promising approach to sustainable material development. This study explores the synthesis of CNTs via chemical vapor deposition (CVD) using mixed cobalt-nickel-iron oxide catalysts supported on alumina and PSW representative polyolefins as carbon sources. The impact of catalyst composition on the yield, morphology, and textural properties of CNTs was systematically evaluated. Characterization techniques, such as textural properties, transmission electron microscopy (TEM), Raman spectroscopy, and thermogravimetric analysis (TGA), revealed that increasing cobalt content in the catalyst resulted in thicker CNT walls (9.2-23.6 nm) and different textural properties (SBET = 47-87 m2 g-1). The synthesized CNTs were then tested in catalytic wet peroxide oxidation (CWPO) for the degradation of sulfamethoxazole (SMX) and bisphenol A (BPA) in both single- and multi-component systems. The results indicated that a higher cobalt content in the CNT catalysts enhanced catalytic activity, particularly for BPA degradation, due to improved H2O2 decomposition. However, a higher leaching of Co and Fe was also observed. The CNTs synthesized with a Co/Ni catalyst composition ratio of 7/3 (CNT@Co0.7Ni0.3) exhibited the best balance among the tested materials in terms of CNTs yield, catalytic activity, and stability. These findings provide valuable insights to optimize CNT catalysts derived from waste plastics for environmental remediation applications.

2025Journal article

Open access