Benny Marie B. Ensano1, Mark Daniel G. de Luna1, Kim Katrina P. Rivera1, Sheila Mae B. Pingul-Ong2, Dennis C. Ong2
1Environmental Engineering Program, College of Engineering (UP Diliman)
2School of Technology (UP Visayas)
Optimization, Isotherm, and Kinetic Studies of Diclofenac Removal from Aqueous Solutions by Fe-Mn Binary Oxide Adsorbents, Environmental Science and Pollution Research, 26: 32407–32419, 2019
This study focused on the removal of diclofenac (DCF), a widely used non-steroidal anti-inflammatory drug, from aqueous solution using Fe–Mn binary oxide (FMBO) adsorbents. The selected FMBO combination takes advantage of the superior adsorption ability of iron (III) oxide and the excellent oxidation potential
of manganese dioxide. The FMBO adsorbents were prepared at varying Fe/Mn molar ratios (1:0, 3:1, and 1:1) through simultaneous oxidation and co-precipitation methods. Batch adsorption experiments were conducted to evaluate the effects of important parameters, such as initial DCF concentration, FMBO dosage, solution pH, and Fe/Mn molar ratio, on DCF removal. Results showed that acidic to neutral pH conditions were more favorable for DCF adsorption while increasing initial DCF concentration and adsorbent dosage resulted in higher DCF removal efficiencies for the three oxides. Lower Fe/Mn molar ratio during FBMO synthesis favored higher DCF removals within a wide pH range. Optimization of operating parameters (initial DCF concentration, FMBO dosage, and solution pH) by Box–Behnken design resulted in up to 28.84 mg g−1 DCF removal for 3:1 FMBO. Isotherm experiments revealed that adsorption occurred on the heterogeneous adsorbent surface. Chemical adsorption was the rate-limiting step of the DCF removal, as best described by the results of the kinetic experiments.
Significance:
This study aimed to address the problem on the presence of the non-steroidal anti-inflammatory drug Diclofenac (DCF) in water resources which, even at very low concentrations, poses a big threat both to human health and aquatic ecosystems. Iron and manganese, which are among the most abundant elements in the Earth’s crust and can also be found in oxide form in industrial wastes such as residuals from deironing and demanganization of underground or infiltration waters, were utilized because of the superior adsorption ability of iron (III) oxide and the excellent oxidation potential of manganese dioxide.
Link to the article: https://doi.org/10.1007/s11356-019-06514-y
Impact factor: (2018/2019) 2.914
Ramon Christian P. Eusebio
Department of Chemical Engineering
College of Engineering and Agro-Industrial Technology
UP Los Baños
Synthesis of Reduced Graphene Oxide/Titanium Dioxide Nanotubes (rGO/TNT) Composites as an Electrical Double Layer Capacitor, Nanomaterials, 8(11): 1-15, 2018
Figure 1. X-ray diffraction pattern of graphene oxide (GO) and reduced graphene oxide (rGO).
Figure 2. X-ray diffraction pattern of titanium dioxide nanotubes (TNT).
Electrical double layer capacitors (ELDCs) are important engineering devices that can be fabricated using specific nanomaterials. EDLCs are mainly used in energy storage where they function as electrodes in two poles—positive and negative. With their ability to store charge/ions, EDLCs have likewise been applied in water treatment technologies such as capacitive deionization. Based on the comparison of different methods of syntheses for rGO/TNT composites, it was evident that the best method would be to synthesize rGO and TNT separately before combining them. Synthesizing both materials separately was shown not to inhibit the formation of the other compound. With regard to proportions, the greatest presence of rGO in general was found to be superior even to pure rGO. 3:1 rGO/TNT attained the desired EDLC behavior, which will perform well in EDLC applications, such as energy storage and capacitive deionization, and will have a better stability as an electrode as it prevents degradation of material due to redox reactions.
Significance:
Composites of synthesized reduced graphene oxide (rGO) and titanium dioxide nanotubes (TNTs) were examined and combined at different mass proportions (3:1, 1:1, and 1:3) to develop an electrochemical double layer capacitor (EDLC) nanocomposite. Electrical double layer capacitors (ELDCs) are important engineering devices that can be fabricated using specific nanomaterials. EDLCs are mainly used in energy storage where they function as electrodes in two poles—positive and negative. With their ability to store charge/ions, EDLCs have likewise been applied in water treatment technologies such as capacitive deionization. In order to assess whether a material can be an EDLC electrode, these properties may be determined through electrochemical means such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). For an EDLC material, a rectangular CV plot with high specific capacitance should be obtained, as this indicates minimized redox reactions during charge transfer, and a steep linear EIS Nyquist plot should be obtained, as this indicates low material resistance.
Link to the article: https://doi.org/10.3390/nano8110934
Impact factor: (2018/2019) 4.034
Ramon Christian P. Eusebio
Department of Chemical Engineering
College of Engineering and Agro-Industrial Technology
UP Los Baños
Sustainable Desalination by 3:1 Reduced Graphene Oxide/Titanium Dioxide Nanotubes (rGO/TiONTs) Composite via Capacitive Deionization at Different Sodium Chloride Concentrations, Nanomaterials, 9(9): 1-13, 2019
Figure 1. Magnified digital images of electrodes after operation at (A) 100 ppm, (B) 2000 ppm, (C) 15,000 ppm, (D) 30,000 ppm, showing an intact arrangement on the titanium current collector plate. No significant accumulation of sodium crystals on the surface were found. Magnification: 50×.
Figure 2. Chronoamperometric plot of CDI at different sodium chloride concentrations showing a consistent current behavior at all concentrations tested. The initial peak observed at the start of each of the operations is due to sudden introduction of 1.2 V to the system while the sudden drop towards the end of the reaction is fue to the removal of this voltage by the instrument, BioLogic SP-150.
Water is a vital resource for domestic, commercial, and industrial activities. However, water resources that serve such purposes are depleting. Given the current population increase and human water consumption behavior, by 2030 there is an expected 40% water supply deficit. This may be addressed by capacitive deionization, an emerging desalination technology that makes possible the removal of ions/salts from a solution. Its performance in salts removal is promising, and it can remove different kinds of ions such as fluorides, calcium, sodium, chloride, potassium, iron (III), magnesium, sulfate, bromide, and nitrate. This study used a composite of reduced graphene oxide (rGO) and titanium dioxide nanotubes (TiONTs) with a mass ratio of 3:1, respectively. The synthesized composite was found to have great potential as an electrode for capacitive deionization in order to perform desalination up to concentrations as high as 30,000 ppm of NaCl. Data gathered showed that 3:1 rGO/TiONTs is capable of recovering salts from water, showing stability even at higher concentrations.
Significance:
Water is a vital resource for domestic, commercial, and industrial activities. However, water resources that serve such purposes are depleting. Aside from the exploitation of useable water sources, the problem is that 96.5% of the world’s available water comes from seas and oceans. Presently, this hindrance poses a challenge with respect to how these potential water sources can be utilized effectively in order to increase supply. For utilizing this huge reservoir, a promising solution is desalination. One of the most helpful technologies developed for this is membrane separation. Although they have made the separation of water from salts possible, most membrane processes are costly due to their high energy demand, making continuous production unsustainable. With this, there is a need to look for alternative processes available. This may be addressed by capacitive deionization, an emerging desalination technology. Capacitive deionization (CDI) is a technology that makes possible the removal of ions/salts from a solution through an electric field generated when the capacitor electrodes are charged. Its performance in salts removal, as reported in studies, is promising, and it can remove different kinds of ions such as fluorides, calcium, sodium, chloride, potassium, iron (III), magnesium, sulfate, bromide, and nitrate.
Link to the article: www.mdpi.com/2079-4991/9/9/1319/pdf
Impact factor: (2018/2019) 4.034
Ramon Christian P. Eusebio
Department of Chemical Engineering
College of Engineering and Agro-Industrial Technology
UP Los Baños
Determination of the Carbon Dioxide Sequestration Potential of a Nickel Mine Mixed Dump Through Leaching Tests Energies, 12 (15): 2877, https://doi.org/10.3390/en12152877, 2019
Figure 1. Block flow diagram of the mineral carbonation process employing the pH swing method.
Figure 2. Schematic diagram of the reactor setup; (1) water condenser, (2) iron ring, (3) rubber tubing, (4) thermometer, (5) glass basin, (6) reactor vessel, (7) oil bath, (8) iron stand, (9) water source, (10) pump, (11) hotplate with magnetic stirrer, and (12) mixture (solvent and sample).
Carbon dioxide sequestration via mineralization is one of the methods that have the capability to efficiently store carbon dioxide in a stable form. A mixed dump sample collected from a nickel laterite mine in Southern Philippines was tested for its carbon dioxide sequestration potential through leaching tests. The study also aimed to optimize the parameters for possible industrial applications, and lastly, to establish the carbon sequestration potential of the mixed dump through a calculation of the theoretical amount of CO2 sequestered per amount of sample. It is reported that the mixed dump can sequester a maximum of 327.2 mg CO2/g sample at 100 °C, 2.5 hours and 2.5 M Hydrochloric acid, which is higher than that of waste cement, blast furnace slag, fly ash, and grounded serpentinite.
Significance:
The increasing threat of global warming has scientists rushing for immediate and sustainable solutions to carbon emissions. Carbon capture and sequestration (CCS) techniques have been perceived as one of the main solutions to the increasing threat of anthropogenic emissions. CCS techniques, methods, and technologies mainly involve the use of a carbon sink, wherein carbon dioxide can be diverted from the atmosphere whilst being stored in a secure and reliable manner. Most of these methods are highly efficient as carbon capture and sequestration can reach up to 100% efficiency for most processes; however, some of these technologies are energy-intensive and cost-ineffective, and thus, cannot be used for industrial application. One particular method stands out among others in terms of its capability to balance the efficiency and energy considerations. CCS via mineralization (CCS-M) is a process in which carbon is stored in geological formations, particularly minerals, which act as the carbon sink. In this study, the applicability of locally available and unutilized mine waste, i.e., mixed dump from a nickel laterite ore mine site, for carbon sequestration is to be determined by varying the process parameters mentioned in leaching tests using the pH swing method.
Link to the article: https://doi.org/10.3390/en12152877
Impact factor: (2018/2019) 2.707
Fernando Siringan1, Danica Linda Mancenido-Cantarero1
1Marine Science Institute, College of Science (UP Diliman)
Off Shore Submarine Groundwater Discharge (SGD) at a Coral Reef Front Controlled Faults, Geochemistry, Geophysics, Geosystems, 20: DOI: 10.1029/2019GC008310, 2019
It has been established that groundwater in sediments can seep or flow into the ocean. Such flow mostly occurs in coastal areas but has also been reported offshore through faults and fractures as pathways. We studied this phenomenon offshore at the northwestern reef front of a reef fringing a limestone island. This area was chosen because of its highly linear outline, which we believe to be a surface manifestation of a fault. In this study, we used methods that distinguish groundwater from seawater through its relatively enriched 222Rn activity, fresher salinity and higher electrical resistivity. We found several sites at the northwestern reef front showing spatial correlation of bottom seawater with relatively enriched 222Rn and fresher salinities with high subsurface resistivity interpreted as sediments saturated with freshwater, suggesting the presence of groundwater flow offshore. The presence of fresh groundwater co-located with the suspected fault orientations at the northwestern and northern reef front also highlights a key role played by faults as conduits for groundwater flow.
Significance:
Establishing the role of faults and fractures as conduits for submarine groundwater flow at the coral reef front in Cape Bolinao, specifically on the edge of the reef fringing in Santiago Island, Bolinao, Pangasinan, Philippines.
Link to the article: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GC008310
Impact factor: (2018/2019) 2.946
