Thermal stability and heavy metal (As5+, Cu2+, Ni2+, Pb2+ and Zn2+) ions uptake of the natural zeolites from the Philippines

2019 ◽  
Vol 6 (8) ◽  
pp. 085204 ◽  
Author(s):  
Eleanor Olegario ◽  
Christian Mark Pelicano ◽  
Jenichi Clairvaux Felizco ◽  
Herman Mendoza
Keyword(s):  
Thermal Stability ◽  
Heavy Metal ◽  
The Philippines ◽  
Natural Zeolites

scholarly journals The Borax Method of Gold Extraction for Small-Scale Miners

2012 ◽  
Vol 2 (3) ◽  
pp. 5-10 ◽  
Author(s):  
Peter W.U. Appel ◽  
Leoncio Na-Oy
Keyword(s):  
Heavy Metal ◽  
Melting Point ◽  
Scientific Research ◽  
The Philippines ◽  
Toxic Element ◽  
Heavy Mineral ◽  
Small Scale ◽  
Gold Extraction ◽  
Reducing Costs ◽  
Capture Rates

Background. More than ten million small-scale miners (SSM) worldwide use mercury to extract gold, releasing large amounts of the toxic element into the environment. Alternatives to mercury have been suggested over the years to little avail. A group of miners in the Philippines has demonstrated that borax, when used as a flux for smelting gold out of heavy mineral concentrates, is an effective and safer substitute for mercury. Objectives. To present a basic comparison of the mercury amalgamation and borax methods of gold extraction for SSM. Methods. Borax was added to milled ore to reduce the melting point of gold to a level accessible to SSM. The amount of gold captured, and the amount of mercury released into the environment, was compared to two common amalgamation methods: whole ore and heavy metal. Discussion. The borax method appears to capture more gold, as well as eliminate the use of mercury. It is also less expensive. It is important to stop the use of mercury amongst SSM. However, health and environmental arguments alone are not enough to convince miners to switch. The argument of improving gold-capture rates while reducing costs is more compelling, and may help propagate the technique among small-scale miners. Conclusions. Scientific research should continue in order to further establish the uses and limitations of the borax method.

scholarly journals Natural zeolites: prospects for heavy metal polluted soil remediation

2020 ◽  
Vol 921 ◽  
pp. 012003
Author(s):  
E A Bocharnikova ◽  
V.P. Shabayev ◽  
V.E. Ostroumov ◽  
D.V. Demin
Keyword(s):  
Heavy Metal ◽  
Soil Remediation ◽  
Polluted Soil ◽  
Natural Zeolites

Levels and Potential Sources of Heavy Metals in Major Irrigated Rice Areas of the Philippines

2015 ◽  
Vol 15 (1) ◽  
Author(s):  
Jehru C. Magahud ◽  
Rodrigo B. Badayos ◽  
Pearl B. Sanchez ◽  
Pompe C. Sta. Cruz
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Irrigation Water ◽  
The Philippines ◽  
Rice Soils ◽  
Rice Plants ◽  
Metal Levels ◽  
Farm Inputs ◽  
Soil Metal ◽  
Very High

Industrialization, urbanization and intensive use of farm inputs can pollute agricultural areas. The study was then conducted to assess the levels of chromium (Cr), nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), arsenic (As), molybdenum (Mo), cadmium (Cd), mercury (Hg), and lead (Pb) in the country’s major rice areas. The study also determined the contributions of soil properties, land uses, irrigation water, and farm inputs to the metal levels. Strategic collections of soil, plant and water samples in the country’s major soil series planted to rice, analyses of samples using x-ray fluorescence or atomic absorption spectroscopy, and farmer interviews were done. Metal levels were very high in Zambales and Negros Occidental soils due to deposition or use of metal-enriched mine tailings and irrigation water. Soil metal concentrations in Zambales far exceeded the intervention values of 180 mg/kg for Cr and 100 mg/kg for Ni. Soil metal levels in Negros Occidental exceeded the intervention value of 190 mg/kg for Cu and Mo. Rice plants in Negros Occidental exceeded the toxic levels of 30 mg/kg for Cu and 10-50 mg/kg for Mo due to the very high soil Cu and Mo concentrations in the area. Molybdenum concentrations of rice plants in Sultan Kudarat and Camarines Sur exceeded the toxic level due to the high amounts of foliar chemicals applied at >66 sprayer loads per year. The study implies that rice areas deposited with mine wastes have high heavy metal levels, and foliar chemicals can increase metal levels in rice.   Keywords - Environmental toxicology, heavy metals, heavy metal sources, rice soils, Philippines

scholarly journals The identification of heavy metal accumulator ferns in abandoned mines in the Philippines with applications to mine rehabilitation and metal recovery

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Rene Juna R. Claveria ◽  
Teresita R. Perez ◽  
Ian A. Navarrete ◽  
Rubee Ellaine C. Perez ◽  
Brian Christian C. Lim
Keyword(s):  
Heavy Metal ◽  
The Philippines ◽  
Metal Recovery ◽  
Abandoned Mines ◽  
Mine Rehabilitation

Host dependent thermal stability and frequency upconversion of Er 3+ -doped heavy metal oxyfluoride germanate glasses

2005 ◽  
Vol 14 (11) ◽  
pp. 2246-2250 ◽  
Author(s):  
Xu Shi-Qing ◽  
Fang Da-Wei ◽  
Zhang Zai-Xuan ◽  
Zhao Shi-Long ◽  
Zhang Li-Yan ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Heavy Metal ◽  
Frequency Upconversion ◽  
Germanate Glasses

Heavy metal ions removal from waste water bythe natural zeolites

2018 ◽  
Vol 5 (9) ◽  
pp. 17930-17934 ◽  
Author(s):  
Shamsan S. Obaid ◽  
D.K. Gaikwad ◽  
M.I. Sayyed ◽  
Khader AL-Rashdi ◽  
P.P. Pawar
Keyword(s):  
Waste Water ◽  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Natural Zeolites ◽  
Heavy Metal Ions Removal ◽  
Metal Ions Removal

Dependence of Thermodynamic and Optical Properties on Glass Compositions in Low-Phonon Energy Heavy-Metal Gallate Glass System

2013 ◽  
Vol 319 ◽  
pp. 49-53
Author(s):  
Xiao Zhe Han ◽  
Fei Wang ◽  
Xin Zhao ◽  
Tie Cheng Ma ◽  
Zhi Qiang Wang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Heavy Metal ◽  
Optical Properties ◽  
Blue Shift ◽  
Glass System ◽  
Phonon Energy ◽  
Light Sources ◽  
Excitation Light ◽  
Optical Fiber Drawing ◽  
Glass Compositions

Dependence of thermodynamic and optical properties on glass compositions in low-phonon energy heavy-metal gallate (MHG) glass system has been investigated. With the increase of Ga2O3and the decrease of Bi2O3, temperature difference value (DT) of Ho3+-doped MHG glasses is increased from 68 °C to 98 °C, in the meantime, thermal stability parameter (H) is enhanced from 0.224 to 0.263, and Saad-Poulain criterion (S) is heightened from 5.59 °C to 13.17 °C. The increments of thermal parameters indicate that the thermal stability against crystallization can be improved for potential optical fiber drawing. The blue shift of cut-off wavelength is confirmed due to the adjustment of glass compositions, which broadens the visible transmittance window, indicating that more options of blue and green excitation light sources make MHG glasses promising candidates for developing functional optoelectronic devices.

scholarly journals Aggregation and thermal properties of nanostructured montmorillonite covered with mixed adsorption layers of cationic polyacrylamide and hazardous lead(II) ions

2020 ◽  
Vol 10 (12) ◽  
pp. 5499-5510
Author(s):  
Małgorzata Wiśniewska ◽  
Gracja Fijałkowska ◽  
Katarzyna Szewczuk-Karpisz ◽  
Dariusz Sternik
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Heavy Metal ◽  
Thermal Properties ◽  
Chemical Nature ◽  
Solid Particles ◽  
Cationic Polyacrylamide ◽  
Low Concentrations ◽  
Adsorption Layers ◽  
Thermal Stability Of

AbstractThe aim of the study was to investigate the influence of nanostructured montmorillonite surface modification by the cationic polyacrylamide and the lead(II) ions on the thermal and aggregation properties of solid particles covered with mixed adsorption layers. The effects of cationic groups content in the polymeric macromolecules, the order of individual adsorbates addition, and lead(II) ions concentration were determined. Using spectrophotometry, potentiometric titration, microelectrophoresis, turbidimetry, DCS (Differential Centrifugal Sedimentation) and thermal analysis methods, the adsorption, electrokinetic, aggregation properties, as well as the thermal stability of studied montmorillonite—CT PAM—Pb(II) systems were established. It was shown that applied polymeric substance (soil flocculant) causes accumulation of lead(II) ions, which are hazardous at very low concentrations. Nevertheless, the chemical nature of these interactions may limit the bioavailability of this heavy metal for plants.

Sign in / Sign up

Export Citation Format

Share Document