Arrowhead Park Early College High School
Mentor(s): Yanyan Zhang, Ph.D. Asst. Professor, Civil Engineering, New Mexico State University
Program: NM AMP SCCORE/REinWEST
Removal of Algal Toxins in Freshwater using Modified Sepiolite Clay
Harmful Algal Blooms (HABs) have increased in their frequency and magnitude and spread over the continents in the past few decades. Severe risks for human health, animals, deleterious effects on commercial fisheries and aquaculture, coastal aesthetics, aquatic ecosystems, and tourism are some major challenges caused by HABs. Microcystins (MCs) are a common algal toxin that imposes adverse effects on kidneys, nervous system, and reproductive system when exposed. In this study, sepiolite clay was modified by chitosan and NH4Fe(SO4)2 to test its feasibility in microcystin-LR (MCLR) removal. When the modified sepiolite was added directly to solutions with the MCLR concentrations of 20-200 µg/L, MCLR removal of 96%-99.9% was observed. The modified sepiolite was packed in dialysis tubes to remove MCLR from the water body with HABs without the risk of releasing it. Interestingly, it was found MCLR removal efficiency increased with the initial MCLR concentrations. Due to the low cost and excellent performance of modified sepiolite, the proposed process can be used for algal toxin removal on a large scale.
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Haoyu B Wang, Environmental Engineering (intended)
Centennial High School
Mentor(s): Pei Xu, New Mexico State University, Professor of Civil Engineering
Program: NM AMP SCCORE
Photocatalytic Degradation of Organic Contaminants in Produced Water
Produced Water is the largest waste stream generated from oil and gas extraction. Produced water is difficult to treat because it contains high levels of salinity and dissolved organics due to millions of years of contact with oil-bearing formations. Removal of organic contaminants is critical to subsequent produced water desalination and to reduce environmental risks. Conventional produced water treatment technologies such as thermal distillation and membrane processes are energy intensive and costly. Photocatalysis is a "green" method of breaking down organics using UV light, which may mineralize the organics into CO2. This project aims to demonstrate photocatalysis as an effective method to degrade the recalcitrant, dissolved petroleum organics in produced water. This study compared two photocatalysts, titanium dioxide (TiO2) nanoparticles and gold modified TiO2 (Au-TiO2). To test the effectiveness of the photocatalysts, Rhodamine B solution was used as an organic indicator. The experimental results showed both catalysts were effective for organic decomposition. The photocatalysis was then applied for produced water samples collected from the Permian Basin. The photocatalysts are shown to decrease the dissolved organic carbon in the produced water by 59%. Further research is needed to further optimize the photocatalysts and evaluate the treatment using sunlight.
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Larissa Zhou, High School (No Major)
Las Cruces High School
Mentor(s): Dr. Hongmei Luo, New Mexico State University, Professor of Chemical and Materials Engineering
Program: NM AMP SCCORE/REinWEST
Li(Ni,Co,Mn)O2 as Cathode Materials for Lithium Ion Batteries
Rechargeable lithium-ion batteries (LIBs) are widely used in cell phones, laptops, and electric vehicles. A LIB cell consists of three main parts: anode, cathode, and electrolyte. The battery type is named after its cathode materials, such as Li(Ni,Co,Mn)O2 (NCM) battery, which is composed of lithium, nickel, cobalt, and manganese. NCM has been the most used cathode for LIB industry due to its considerable capacity and energy density. NCM has different compositions, such as LiNi0.5Co0.2Mn0.3O2 (NCM 523), LiNi0.6Co0.2Mn0.2O2 (NCM 622), and LiNi0.8Co0.1Mn0.1O2 (NCM 811). With the applied NCM 622 and NCM 811 cathodes in coin cells in this research, the goal is to test their battery performance and to understand the composition effects on their electrochemical properties. From the charge-discharge and cycling performance measurements, NCM 811 shows higher capacity and better stability as compared to NCM 622. Future work will employ X-ray diffraction and electron microscopes to examine the phase, morphology, crystal structure, and microstructure and to explore the relationship between composition, structure and battery performance. The goal is to have safe batteries with higher capacity, long cycling life and higher energy and power densities.
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