Degree: Doctor

This CIQUP member does not yet have any projects linked with him.
Showing 5 latest publications. Total publications: 109
Show all publications
1. Chemiluminescent Self-Activating Photosensitizers for Selective Anticancer Therapy, Magalhães, CM; González-Berdullas, P; Silva, JCGEd Silva, LPd in ECMC 2022, 2022,
Proceedings Paper,  Indexed in: crossref  DOI: 10.3390/ecmc2022-13174 P-00X-P3P

2. UV-Based Advanced Oxidation Processes of Remazol Brilliant Blue R Dye Catalyzed by Carbon Dots, Cardoso, IMF; Cardoso, RMF; da Silva, LP da Silva, JCGE in NANOMATERIALS, 2022, Volume: 12, 
Article,  Indexed in: crossref, wos  DOI: 10.3390/nano12122116 P-00W-RHD
Abstract UV-based advanced oxidation processes (AOPs) (UV/H2O2 and UV/S2O82-) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at T = 25 degrees C and pH = 7). The Ti-CD, with marked catalytic UV properties, was successfully synthesized by the one-pot hydrothermal procedure, using L-cysteine as carbon precursor, ethylenediamine as nitrogen source, PEG (polyethylene glycol) as a capping agent, and titanium(IV) isopropoxide (precursor of TiO2 doping). Contrary to azo dyes (methyl orange, orange II sodium salt, and reactive black 5), which achieved complete degradation in a time interval less than 30 min in the developed AOP systems (UV/H2O2, UV/S2O82-, and UV/TiO2), the RBB-R showed relatively low degradation rates and low discoloration rate constants. In the presence of the catalyzer, the reaction rate significantly increased, and the pseudo-first-order rate constants for the RBB-R discoloration were UV/3.0 mM H2O2/TIP-CD-0.0330 min(-1) and UV/1.02 mM S2O82-/TIP-CD-0.0345 min(-1).

3. Photocatalytic removal of pharmaceutical water pollutants by TiO2-Carbon dots nanocomposites: A review, Sendao, RMS; da Silva, JCGE da Silva, LP in CHEMOSPHERE, 2022, ISSN: 0045-6535,  Volume: 301, 
Review,  Indexed in: crossref, scopus, wos  DOI: 10.1016/j.chemosphere.2022.134731 P-00W-EXY
Abstract Pharmaceuticals are becoming increasingly more relevant water contaminants, with photocatalysts (such as TiO2) being a promising approach to remove these compounds from water. However, TiO2 has poor sunlight harvesting capacity, low photonic efficiency, and poor adsorption towards organic pollutants. One of the emerging strategies to enhance the photocatalytic performance of TiO2 is by conjugating it with fluorescent carbon dots. Herein, we performed a critical review of the development of TiO2 - carbon dots nanocomposites for the photocatalytic removal of pharmaceuticals. We found that carbon dots can improve the photocatalytic efficiency of the resulting nanocomposites, mostly due to increasing the adsorption of organic pollutants and enhancing the absorption in the visible range. However, while this approach shows significant promise, we also identified and discussed several aspects that need to be addressed before this strategy could be more widely used. We hope that this review can guide future studies aiming to the development of enhanced photocatalytic TiO2 - carbon dots nanocomposites.

4. Development of a Coelenterazine Derivative with Enhanced Superoxide Anion-Triggered Chemiluminescence in Aqueous Solution, Silva, JP; Gonzalez-Berdullas, P; da Silva, JCGE da Silva, LP in CHEMOSENSORS, 2022, ISSN: 2227-9040,  Volume: 10, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.3390/chemosensors10050174 P-00W-GYS
Abstract Superoxide anion is a reactive oxygen species (ROS) of biological interest. More specifically, it plays a role in intra- and intercellular signaling, besides being associated with conditions such as inflammation and cancer. Given this, efforts have been made by the research community to devise new sensing strategies for this ROS species. Among them, the chemiluminescent reaction of marine Coelenterazine has been employed as a sensitive and dynamic probing approach. Nevertheless, chemiluminescent reactions are typically associated with lower emissions in aqueous solutions. Herein, here we report the synthesis of a new Coelenterazine derivative with the potential for superoxide anion sensing. Namely, this novel compound is capable of chemiluminescence in a dose-dependent manner when triggered by this ROS species. More importantly, the light-emission intensities provided by this derivative were relevantly enhanced (intensities 2.13 x 10(1) to 1.11 x 10(4) times higher) in aqueous solutions at different pH conditions when compared to native Coelenterazine. The half-life of the chemiluminescent signal is also greatly increased for the derivative. Thus, a new chemiluminescence molecule with significant potential for superoxide anion sensing was discovered and reported for the first time.

5. Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes, Cardoso, RMF; Cardoso, IMF; da Silva, LP da Silva, JCGE in NANOMATERIALS, 2022, Volume: 12, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.3390/nano12071211 P-00W-BQZ
Abstract A catalytic ozonation advanced oxidation process (AOP) with a copper(II)-doped carbon dot as catalyst, Cu-CD (using L-cysteine and polyethylene glycol (PEG) as precursors and passivation agents), was developed for textile wastewater treatment (T = 25 degrees C and pH = 7). Four dyes were analyzed-Methyl Orange (MO), Orange II sodium salt (O-II), Reactive Black 5 (RB-5) and Remazol Brilliant Blue R (RBB-R), as well as a real effluent from the dying and printing industry. The Cu-CD, with marked catalytic ozonation properties, was successfully synthesized by one-pot hydrothermal procedure with a size of 4.0 nm, a charge of -3.7 mV and a fluorescent quantum yield of 31%. The discoloration of the aqueous dye solutions followed an apparent first-order kinetics with the following rate constants (k(ap) in min(-1)): MO, 0.210; O-II, 0.133; RB-5, 0.177; RBB-R, 0.086. In the presence of Cu-CD, the following apparent first-order rate constants were obtained (k(ap)(C) in min(-1)) with the corresponding increase in the rate constant without catalyst (%Inc): MO, 1.184 (464%); O-II, 1.002 (653%); RB-5, 0.709 (301%); RBB-R, 0.230 (167%). The presence of sodium chloride (at a concentration of 50 g/L) resulted in a marked increase of the discoloration rate of the dye solution due to generation of other radicals, such as chlorine and chlorine oxide, resulting from the reaction of ozone and chloride. Taking into consideration that the real textile effluent under research has a high carbonate concentration (>356 mg/L), which inhibits ozone decomposition, the discoloration first-order rate constants without and with Cu-CD (k(ap) = 0.0097 min(-1) and k(ap)(C) = 0.012 min(-1) (%Inc = 24%), respectively) were relatively small. Apparently, the Cu-CD, the surface of which is covered by a soft and highly hydrated caramelized PEG coating, accelerates the ozone decomposition and dye adsorption, increasing its degradation.