scholarly journals Removal of nitrate using modified pumice as adsorbent for reducing groundwater pollution

2021 ◽  
Vol 331 ◽  
pp. 02012
Author(s):  
Shinta Indah ◽  
Denny Helard ◽  
Gusti Lusiani ◽  
Diana Hapsari
Keyword(s):  
Removal Efficiency ◽  
Groundwater Pollution ◽  
Room Temperature ◽  
Nitrate Uptake ◽  
Sem Images ◽  
Chemical Treatments ◽  
Chemically Modified ◽  
Batch System ◽  
Nitrate Adsorption ◽  
Physical And Chemical

Nitrate adsorption onto the physically and chemically modified pumice was investigated as an effort for reducing groundwater pollution. The treatments were heating at temperatures of 300°C, 450°C, and 600°C for physical and soaking in acid solutions (HCl, H2SO4, and HNO3) for chemical treatments. The adsorption was performed in a batch system at room temperature (25±1°C) with the optimum condition (pH 4; 0.3 g/L of adsorbent dose; <63 µm of adsorbent diameters and 30 minutes of contact time). The results indicated that the physically and chemically modified pumice resulted in increasing removal efficiency and nitrate uptake compared to the natural pumice. The highest removal efficiency and nitrate uptake were achieved from 300°C of heating temperatures (62.04% and 155.09 mg/g) and H2SO4 for the acid solution (83.30% and 208.25 mg/g), while by using the natural pumice only reached 57.02 % and 142.55 mg/g. The SEM images of the modified pumice confirmed the change in the surface morphology of pumice including the pore structure and surface area which can be proper sites for adsorption of pollutants. This study demonstrated that physical and chemical modification could be the potential treatment to increase the removal efficiency and nitrate uptake of the natural pumice, thus can solve the problem of groundwater pollution.

scholarly journals Modification of natural pumice by physical and chemical treatments for removal of zinc ions from aqueous solution

2019 ◽  
Vol 276 ◽  
pp. 06009
Author(s):  
Shinta Indah ◽  
Denny Helard ◽  
Budhi Primasari ◽  
Tivany Edwin ◽  
Riyan Hexa Putra
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Metal Uptake ◽  
Chemical Treatments ◽  
Batch System ◽  
Zn Uptake ◽  
Zn Concentration ◽  
West Sumatra ◽  
Modification Technique ◽  
Physical And Chemical

To increase the adsorption capability of natural pumice from Sungai Pasak, West Sumatra, Indonesia in removal of Zn from aqueous solution, modification by physical and chemical treatments were evaluated. The treatments were heating at temperatures of 300°C, 450°C, and 600°C for physical and soaking in acid solutions (HCl, H2SO4, and HNO3) for chemical treatments. The adsorption was performed in batch system with the optimum condition (6 of pH solution, < 63 um of adsorbent diameter, 3 g/L of adsorbent dose, 5 mg/L of Zn concentration, and 15 min of contact time). The results revealed that the removal efficiency and Zn uptake increase using modified pumice from 68.83% and 1.15 mg/g to 74.46% and 1.24 mg/g. The highest removal efficiency and Zn uptake were obtained from 300°C of heating temperatures and HCl for acid solution. The application of modified adsorbent for removal of Zn from aqueous solution showed that the modification technique has the potential to increase the removal efficiency and metal uptake of the natural pumice.

scholarly journals Performance during post-harvest storage of banana cv. 'prata', 'maçã' and 'nanica' exposed to physical and chemical treatments

2011 ◽  
Vol 31 (4) ◽  
pp. 727-734 ◽  
Author(s):  
Silvia R. M. Coelho ◽  
Simone S. Werner ◽  
Anna P. Poncio ◽  
Letícia Ferreira ◽  
Lúcia H. P. Nóbrega
Keyword(s):  
Room Temperature ◽  
Titratable Acidity ◽  
Mineral Oil ◽  
Hot Water ◽  
Soluble Solids ◽  
Post Harvest ◽  
Chemical Treatments ◽  
Peel Color ◽  
The World ◽  
Physical And Chemical

Banana is the most consumed fruit in the world and Brazil is the second largest producer. Despite its global position, Brazil has an average of 40% losses during the post-harvest period. So, this experiment aimed at evaluating the efficiency of post-harvest treatments to improve the storage of banana cultivars cv. 'Prata', 'Maçã' and 'Nanica'. The fruits were acquired at CEASA with green peel, and were submitted to six different treatments: T- immersion in drinking water for 3 minutes (control), H3 - hot water (50 °C for 3 minutes), H8 - hot water (50 °C for 8 minutes), HP - immersion in hypochlorite 0.2% for 3 minutes, OS - immersion in soybean oil 10% for 3 minutes, and OM - immersion in mineral oil 10% for 3 minutes. The fruits were stored at room temperature at about 21 °C for 14 days and evaluated in three periods (1, 7 and 14 days) comparing peel color, flesh/peel ratio, titratable acidity (TA), soluble solids (SS), SS/TA ratio, and pH. The fruits of cv. 'Prata' and 'Maçã' submitted to the treatments H3, H8 and HP ripened at the same time as the control for peel color, which showed increased soluble solids, flesh/peel ratio, acidity and a decrease in pH. On the other hand, the cv. 'Nanica' did not respond significantly different when compared to the applied treatments and the control. The fruits treated with OM and OS were kept green for a longer time for the cultivars 'Prata' and 'Nanica', but there were some changes on peel color due dark spots in 'Prata' banana and a softening aspect in 'Nanica', indicating some level of toxicity of these treatments. Fruits of the 'Maçã' cultivar continued green with the application of mineral oil, without toxicity symptoms. In conclusion, the treatments applied did not show any advantage for storage of these fruits.

scholarly journals Bonding Behavior and Mechanism of U(VI) by Chemically Modified Deinococcus radiodurans

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1108
Author(s):  
Xiaoqin Nie ◽  
Faqin Dong ◽  
Mingxue Liu ◽  
Wencai Cheng ◽  
Congcong Ding ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Deinococcus Radiodurans ◽  
Lipid Fraction ◽  
Lipid Extraction ◽  
Order Kinetic ◽  
Oh Groups ◽  
Chemical Treatments ◽  
Chemically Modified ◽  
Pseudo Second Order

The goal of this study is to understand the role of various functional groups on the cell surface when the microorganisms are exposed to uranium (U(VI)). The biomass of Deinococcus radiodurans was subjected to chemical treatments to modify the carboxyl (-C=O), amino (-NH2), phosphate (-PO2−), and hydroxyl (-OH) groups, as well as the lipid fraction. The behavior and process of U(VI) biosorption by Deinococcus radiodurans were ascertained, followed by scanning electron microscopy (SEM) combined with energy disperse spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) analyses. Carboxyl esterification and amino methylation deteriorated the removal efficiency by 8.0% and 15.5%, respectively, while lipid extraction, phosphate esterification, and hydroxyl methylation improved the removal efficiency by 11.7%, 8.7%, and 4.1%, respectively. The kinetic results revealed that uranium biosorption behavior by the raw and chemically modified biomass fitted well with the model of pseudo-second-order kinetic (R2 = 0.9949~0.9998). FTIR and SEM-EDS indicated that uranium initially bound with the raw and chemically modified Deinococcus radiodurans, which was probably controlled by ion exchange at the first stage, followed by complexation with the -C=O and -NH2 groups, which especially prefer to bond with P and O atoms on the -PO2− group.

Chromosomal analysis of mouse spermatozoa following physical and chemical treatments that are effective in inactivating HIV

Zygote ◽  
2004 ◽  
Vol 12 (4) ◽  
pp. 339-344 ◽  
Author(s):  
Kazuto Morozumi ◽  
Hiroyuki Tateno ◽  
Kaoru Yanagida ◽  
Haruo Katayose ◽  
Yujiroh Kamiguchi ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Room Temperature ◽  
Sodium Hypochlorite Solution ◽  
Chromosome Damage ◽  
Hypochlorite Solution ◽  
Chemical Treatments ◽  
Immunodeficiency Virus ◽  
Structural Chromosome ◽  
Sperm Nuclei ◽  
Physical And Chemical

Human immunodeficiency virus (HIV) can be inactivated by heating at 56 °C for 30 min, treating with 50% ethanol at room temperature for 10 min, or treating with 2% sodium hypochlorite solution (NaClO) at room temperature for 60 min. Using a mouse model, we evaluated the risk of generating chromosome damage in spermatozoa following these treatments. The spermatozoa were all dead after the treatments. Although 41.3% of oocytes injected with ethanol-treated spermatozoa successfully activated, none of the oocytes injected with heated or NaClO-treated spermatozoa activated. When artificial stimulation with strontium was used, the fertilization of oocytes with heated or ethanol-treated spermatozoa was completely rescued. Sperm nuclei treated with NaClO neither decondensed nor developed to a male pronucleus. The incidences of structural chromosome aberrations in 1-cell zygotes derived from the heated spermatozoa (45.6%) and ethanol-treated spermatozoa (91.2%) were significantly higher than those in the matched controls (5.5% and 10.5%, respectively). Further study is needed to develop a methodology for the protection of spermatozoa against chromosome damage or the separation of damaged spermatozoa before intracytoplasmic sperm injection.

scholarly journals Composite Material of PDMS with Interchangeable Transmittance: Study of Optical, Mechanical Properties and Wettability

2021 ◽  
Vol 5 (4) ◽  
pp. 110
Author(s):  
Flaminio Sales ◽  
Andrews Souza ◽  
Ronaldo Ariati ◽  
Verônica Noronha ◽  
Elder Giovanetti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Room Temperature ◽  
Casting Process ◽  
Optical Characteristics ◽  
Smart Devices ◽  
Superhydrophobic Coating ◽  
Gravity Casting ◽  
High Flexibility ◽  
Physical And Chemical

Polydimethylsiloxane (PDMS) is a polymer that has attracted the attention of researchers due to its unique properties such as transparency, biocompatibility, high flexibility, and physical and chemical stability. In addition, PDMS modification and combination with other materials can expand its range of applications. For instance, the ability to perform superhydrophobic coating allows for the manufacture of lenses. However, many of these processes are complex and expensive. One of the most promising modifications, which consists of the development of an interchangeable coating, capable of changing its optical characteristics according to some stimuli, has been underexplored. Thus, we report an experimental study of the mechanical and optical properties and wettability of pure PDMS and of two PDMS composites with the addition of 1% paraffin or beeswax using a gravity casting process. The composites’ tensile strength and hardness were lower when compared with pure PDMS. However, the contact angle was increased, reaching the highest values when using the paraffin additive. Additionally, these composites have shown interesting results for the spectrophotometry tests, i.e., the material changed its optical characteristics when heated, going from opaque at room temperature to transparent, with transmittance around 75%, at 70 °C. As a result, these materials have great potential for use in smart devices, such as sensors, due to its ability to change its transparency at high temperatures.

scholarly journals Clean one-pot multicomponent synthesis of pyrans using a green and magnetically recyclable heterogeneous nanocatalyst

SynOpen ◽  
2021 ◽  
Author(s):  
Mina Ghassemi ◽  
Ali Maleki
Keyword(s):  
Room Temperature ◽  
Significant Loss ◽  
Copper Ferrite ◽  
Multicomponent Synthesis ◽  
Thermo Gravimetric ◽  
Sem Images ◽  
One Pot ◽  
Three Component Reaction ◽  
Ft Ir ◽  
The One

Copper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition method and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde and a β-ketoester in ethanol at room temperature. Then it was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) analysis, scanning electron microscopy (SEM) images, thermo gravimetric and differential thermo gravimetric (TGA/DTG) analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, no use of eternal energy source and using a green solvent provide benign, mild, and environmentally friendly reaction conditions; as well, ease of catalyst recovering, catalyst recyclability, no use of column chromatography and good to excellent yields are extra advantages of this work.

scholarly journals Room Temperature Syntheses of ZnO and Their Structures

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 733
Author(s):  
Domenica Donia ◽  
Elvira Maria Bauer ◽  
Mauro Missori ◽  
Ludovica Roselli ◽  
Daniele Cecchetti ◽  
...  
Keyword(s):  
Room Temperature ◽  
Direct Synthesis ◽  
Threshold Value ◽  
Rietveld Analysis ◽  
Synthesis Temperature ◽  
Density Variation ◽  
Controlled Synthesis ◽  
Sem Images ◽  
Aqueous Solvent ◽  
Average Size

ZnO has many technological applications which largely depend on its properties, which can be tuned by controlled synthesis. Ideally, the most convenient ZnO synthesis is carried out at room temperature in an aqueous solvent. However, the correct temperature values are often loosely defined. In the current paper, we performed the synthesis of ZnO in an aqueous solvent by varying the reaction and drying temperatures by 10 °C steps, and we monitored the synthesis products primarily by XRD). We found out that a simple direct synthesis of ZnO, without additional surfactant, pumping, or freezing, required both a reaction (TP) and a drying (TD) temperature of 40 °C. Higher temperatures also afforded ZnO, but lowering any of the TP or TD below the threshold value resulted either in the achievement of Zn(OH)2 or a mixture of Zn(OH)2/ZnO. A more detailed Rietveld analysis of the ZnO samples revealed a density variation of about 4% (5.44 to 5.68 gcm−3) with the synthesis temperature, and an increase of the nanoparticles’ average size, which was also verified by SEM images. The average size of the ZnO synthesized at TP = TD = 40 °C was 42 nm, as estimated by XRD, and 53 ± 10 nm, as estimated by SEM. For higher synthesis temperatures, they vary between 76 nm and 71 nm (XRD estimate) or 65 ± 12 nm and 69 ± 11 nm (SEM estimate) for TP =50 °C, TD = 40 °C, or TP = TD = 60 °C, respectively. At TP = TD = 30 °C, micrometric structures aggregated in foils are obtained, which segregate nanoparticles of ZnO if TD is raised to 40 °C. The optical properties of ZnO obtained by UV-Vis reflectance spectroscopy indicate a red shift of the band gap by ~0.1 eV.

Effects of physical and chemical treatments upon biophysical properties and micro-relief of human skin

2008 ◽  
Vol 300 (5) ◽  
pp. 243-251 ◽  
Author(s):  
Nicolas Atrux-Tallau ◽  
Ngoc T. T. Huynh ◽  
Laurie Gardette ◽  
Cyril Pailler-Mattéi ◽  
Hassan Zahouani ◽  
...  
Keyword(s):  
Human Skin ◽  
Biophysical Properties ◽  
Chemical Treatments ◽  
Physical And Chemical

Cryogenic Interlaminar Properties of PBO Fiber/Epoxy Composites

2011 ◽  
Vol 391-392 ◽  
pp. 1445-1449
Author(s):  
Chun Hua Zhang ◽  
Shi Lin Luan ◽  
Xiu Song Qian ◽  
Bao Hua Sun ◽  
Wen Sheng Zhang
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Epoxy Composites ◽  
Bending Test ◽  
Test Results ◽  
Sem Images ◽  
Three Point Bending ◽  
Pbo Fiber ◽  
Interlaminar Shear

The influences of low temperature on the interlaminar properties for PBO fiber/epoxy composites have been studied at liquid nitrogen temperature (77 K) in terms of three point bending test. Results showed that the interlaminar shear strength at 77 K were significantly higher than those at room temperature (RT). For the analysis of the test results, the tensile behaviors of epoxy resin at both room temperature and liquid nitrogen temperature were investigated. The interface between fiber and matrix was observed using SEM images.

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