Liz Diaz

University of Puerto Rico at Rio Piedras | UPR-RP · Department of Chemistry

Tin (Sn) metal has emerged as a promising anode for aqueous batteries, due to its high capacity, non‐toxicity, and cost‐effectiveness. However, Sn metal has often been coupled with strong and corrosive sulfuric acids (2–3 M), leading to severe electrode corrosion and hydrogen evolution issues. Although high efficiency and long cycling were reported...

This study addresses the persistent challenge of polysulfide dissolution in lithium–sulfur (Li–S) batteries by introducing magnesium oxide (MgO) nanoparticles as a novel additive. MgO was integrated with sulfur using a scalable process involving solid-state melt diffusion treatment followed by planetary ball milling. XRD measurements confirmed that...

Tin (Sn) metal has emerged as a promising anode for aqueous batteries, due to its high capacity, non‐toxicity, and cost‐effectiveness. However, Sn metal has often been coupled with strong and corrosive sulfuric acids (2‐3 M), leading to severe electrode corrosion and hydrogen evolution issues. Although high efficiency and long cycling were reported...

This document presents a simple yet highly effective demonstration for creating UV radiation sensors using alginate molecules. This demonstration can easily be aligned with the Next Generation Science Standards (NGSS) for classroom use. Moreover, the demonstration requires only a few easily obtainable materials, and the process involved is straight...

Sulfur holds immense promise for battery applications owing to its abundant availability, low cost, and high capacity. Currently, sulfur is commonly combined with alkali or alkaline earth metals in metal–sulfur batteries. However, these batteries universally face challenges in cycling stability due to the inevitable issue of polysulfide dissolution...

Based on the search for new biodegradable materials that are low cost and easy to synthesize by environmentally friendly methods, we report the use of carrageenan membranes (mixture of κ and λ carrageenans) with different concentrations of titanium dioxide nanoparticles (TiO2 NPs) and Ni/CeO2 (10 wt % Ni) for the fabrication of a novel fuel cell el...

Worsening environmental conditions due to climate change have profoundly affected the health of coral reefs worldwide. Thus, understanding how corals respond to fluctuating and/or extreme levels of temperature and solar irradiation will guide future protection and restoration efforts of this valuable ecosystem. Herein, we present a study of the imm...

One of the main attributes that highlight the final quality of a gourmet cup of coffee is its aroma. Aromas vary according to a variety of plant and environmental variables, among others. This study aimed to characterize volatile and semivolatile compounds according to the Coffee arabica "Limani" berries ripening stages (healthy and brocaded). The...

Microalgae peptides have many medical and industrial applications due to their functional properties. However, the rapid degradation of peptides not naturally present in biological samples represents a challenge. A strategy to increase microalgae peptide stability in biological samples is to use carriers to protect the active peptide and regulate i...

Polyphenols are natural compounds with strong antioxidant properties synthesized by plants and widely distributed in plant tissues. They compose a broad class of compounds that are commonly employed for multiple applications such as food, pharmaceutical, adhesives, biomedical, agricultural, and industrial purposes. Runoffs from these sources result...

Society has long been exposed to naturally-occurring nanoparticles. Due to their ubiquitous nature, biological systems have adapted and built protection against their potential effects. However, for the past decades, there have been onslaughts of newly engineered nanoparticles being released in the environment with no known effects on ecosystems. A...

La nanociencia y la nanotecnología forman parte del desarrollo científico-tecnológico que contemplamos en la actualidad. Para educar en sus conceptos y diseminarlos en la sociedad se requiere de la creación de nuevas estrategias educativas. En este artículo describimos la investigación-acción realizada para la planificación, diseño y desarrollo de...

Background The roles of gorgonian sclerites as structural components and predator deterrents have been widely studied. Yet their role as barriers against microbes has only recently been investigated, and even less is known about the diversity and roles of the chemical compounds associated with sclerites. Methods Here, we examine the semi-volatile...

List of semivolatile organic compounds (SVOCs) isolated from sclerites from: healthy fans (HH), from healthy tissue from diseased fans (HD) and diseased tissue (DD) and their respective roles.

Determining the catalytic activity of an enzyme can be the perfect method for its identification, for example during purification procedures or for isolation purposes. Herein, we used a pharmaceutically relevant protein to bring the concept of enzymatic activity to the classroom. We designed a hands-on interactive activity in which a medically rele...

Herein, we study the feasibility of using nanocellulose (NC)-based composites with silver and platinum nanoparticles as additive materials to fabricate the support layer of thin film composite (TFC) membranes for water purification applications. In brief, the NC surface was chemically modified and then was decorated with silver and platinum nanopar...

Among several Puerto Rican algae, Sargassum sp. (SG) and Chaetomorpha (CM) showed the highest phenol adsorption capacity from aqueous solutions and were used in optimized adsorption batch experiments at room temperature. The effects of pH, adsorbent dose, phenol concentration, salinity and presence of interfering substances were evaluated. Initial...

We report a comprehensive quantitative study of the production of refined bio-crudes via a controlled hydrothermal liquefaction (HTL) process using Ulva fasciata macroalgae (UFMA) as biomass and ultrananocrystalline Fe3O4 (UNCFO) as catalyst. X-ray diffraction and electron microscopy were applied to elucidate the formation of the high-quality nanoc...

The optical properties of gold nanoparticles depend on particles size, shape, protective ligand and the synthesis method used for their production. The present study describes an eco-friendly method for the synthesis of gold Nanoparticles (AuNPs) utilizing the macro algae Osmundaria Obtusiloba. The optical properties of the obtained nanoparticles a...

Algae biomasses are considered a viable option for the production of biofuel because of their high yields of oil produced per dry weight. Brown macroalgae Sargassum spp. are one of the most abundant species of algae in the shores of Puerto Rico. Its availability in large quantity presents a great opportunity for use as a source of renewable energy....

Algae biomasses are considered a viable option for the production of biofuel because of their high yields of oil produced per dry weight. Brown macroalgae Sargassum spp. are one of the most abundant species of algae in the shores of Puerto Rico. Its availability in large quantity presents a great opportunity for use as a source of renewable energy....

Nanotechnology allows the synthesis of nanoscale catalysts, which offer an efficient alternative for fuel cell applications. In this laboratory experiment, the student selects a cost-effective anode for fuel cells by comparing three different working electrodes. These are commercially available palladium (Pd) and glassy carbon (GC) electrodes, and...

Activity looks at how ocean acidification affects coral reef growth. Students define/utilize pH acidity scale, explain carbon dioxide and its impact on atmosphere and the ocean. Connects pH, carbon cycle, and coral reef growth, as well as conservation issues related to ocean acidification and affects on coral reef ecosystem.

The integration of research and education is an essential component of our university’s teaching philosophy. Recently, we made a curricular revision to facilitate such an approach in the General Chemistry Laboratory, to teach students that investigative approaches are at the core of sciences. The curriculum revision included new interdisciplinary e...

A general chemistry experiment has been adapted in which electrochemical principles in fuel cells are applied to the curriculum, thus bringing research into the classroom. It is well documented that students struggle in understanding redox reactions, in particular when applied to an electrochemical cell. There are three basic concepts needed to ana...

Fatty acid ethyl esters (FAEE) are known to be a direct alcohol marker and are mainly investigated in hair samples for their ability to be incorporated into this matrix from sebum. The present study used an already developed methodology to provide and confirm information about the use of FAEEs in skin surface lipids as markers of alcohol consumptio...

Endocrine disruptor compounds are able to mimic or antagonize the effects of endogenous hormones. Phenolic compounds are one of the most abundant classes of endocrine disruptors due to their presence in a broad range of chemical manufacturing processes. The detection of such compounds in food, medicine, and the environment (i.e., water) is crucial...

Methodology using MAE/SPME/GC-MS is being pursued for the analysis of organic pollutants in sebum. The microwave-assisted extraction (MAE) of standards of semi volatile organic pollutants from sebum was optimized. All compounds were extracted from sebum with recoveries analyzed by GC/MS ranging from 94% to 100% under the optimum MAE conditions: 10m...