UiO-66(Zr)-derived t-zirconia with abundant lattice defect for remarkably enhanced arsenic removal

A new specimen preparation technique for visualizing macromolecules by conventional transmission electron microscopy has been developed. In this technique the biopolymer-molecule is embedded in a thin monocrystalline gold foil. Such embedding can be performed in the following way: the biopolymer is deposited on an epitaxially-grown thin single-crystal gold film. The molecule is then occluded by further epitaxial growth. In such an epitaxial sandwich an occluded molecule is expected to behave as a crystal-lattice defect and give rise to contrast in the electron microscope.The resolution of the method should be limited only by the precision with which the epitaxially grown gold reflects the details of the molecular structure and, in favorable cases, can approach the lattice resolution limit.In order to estimate the strength of the contrast due to the void-effect arising from occlusion of the DNA-molecule in a gold crystal some calculations were performed.

Download Full-text

LATTICE DEFECT EFFECTS IN INDUCED CURRENT SCANNING MICROSCOPY

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1983436 ◽

1983 ◽

Vol 44 (C4) ◽

pp. C4-305-C4-311

Author(s):

A. Castaldini ◽

A. Cavallini ◽

P. Gondi

Keyword(s):

Lattice Defect ◽

Scanning Microscopy ◽

Induced Current

Download Full-text

IRON OXIDES FROM ELECTROFILTER ASH FOR WATER TREATMENT (ARSENIC REMOVAL)

Environmental Engineering and Management Journal ◽

10.30638/eemj.2009.128 ◽

2009 ◽

Vol 8 (4) ◽

pp. 895-900 ◽

Cited By ~ 2

Author(s):

Ionel Balcu ◽

Adina Segneanu ◽

Marius Mirica ◽

Mirela Iorga ◽

Catalin Badea ◽

...

Keyword(s):

Water Treatment ◽

Iron Oxides ◽

Arsenic Removal

Download Full-text

As(III) Removal by Dynamic Adsorption onto Amberlite XAD7 Functionalized with Crown Ether and Doped with Fe(III) Ions

Revista de Chimie ◽

10.37358/rc.19.7.7333 ◽

2019 ◽

Vol 70 (7) ◽

pp. 2330-2334

Author(s):

Mihaela Ciopec ◽

Adina Negrea ◽

Narcis Duteanu ◽

Corneliu Mircea Davidescu ◽

Iosif Hulka ◽

...

Keyword(s):

Adsorption Process ◽

Arsenic Removal ◽

Arsenic Concentration ◽

Fixed Bed ◽

World Health ◽

Arsenic Content ◽

Arsenic Adsorption ◽

Stage Of Development ◽

Wide Range ◽

Health Organization

Arsenic content in groundwater�s present a wide range of concentration, ranging from hundreds of micrograms to thousands of micrograms of arsenic per litter, while the maximum permitted arsenic concentration established by World Health Organization (WHO) is 10 mg L-1. According to the WHO all people, regardless of their stage of development and their social economic condition, have the right to have access to adequate drinking water. The most efficient and economic technique used for arsenic removal is represented by adsorption. In order to make this remediation technique more affordable and environmentally friendly is important to new materials with advance adsorbent properties. Novelty of present paper is represented by the usage of a new adsorbent material obtained by physical - chemical modification of Amberlite XAD polymers using crown ethers followed by iron doping, due to well-known affinity of arsenic for iron ions. Present paper aims to test the obtained modified Amberlite polymer for arsenic removal from real groundwater by using adsorption in a fixed bed column, establishing in this way a mechanism for the adsorption process. During experimental work was studied the influence of competing ions from real water into the arsenic adsorption process.

Download Full-text

Arsenic removal by MF membrane with chemical sludge adsorption and NF membrane equipped with vibratory shear enhanced process

Water Science & Technology Water Supply ◽

10.2166/ws.2003.0182 ◽

2003 ◽

Vol 3 (5-6) ◽

pp. 303-310 ◽

Cited By ~ 2

Author(s):

S.-H. Yi ◽

S. Ahmed ◽

Y. Watanabe ◽

K. Watari

Keyword(s):

Arsenic Removal ◽

Membrane Surface ◽

Membrane Process ◽

Low Concentrations ◽

Strong Shear ◽

Low Levels ◽

Removal Processes ◽

Removal Of Arsenic ◽

Concentration Polarization Layer ◽

Chemical Sludge

Conventional arsenic removal processes have difficulty removing low concentrations of arsenic ion from water. Therefore, it is very hard to comply with stringent low levels of arsenic, such as below 10 μg/L. So, we have developed two arsenic removal processes which are able to comply with more stringent arsenic regulations. They are the MF membrane process combined with chemical sludge adsorption and NF membrane process equipped with the vibratory shear enhanced process (VSEP). In this paper, we examine the performance of these new processes for the removal of arsenic ion of a low concentration from water. We found that chemical sludge produced in the conventional rapid sand filtration plants can effectively remove As (V) ions of H2AsO4- and HAsO42- through anion exchange reaction. The removal efficiency of MF membrane process combined with chemical sludge adsorption increased to about 36%, compared to MF membrane alone. The strong shear force on the NF membrane surface produced by vibration on the VSEP causes the concentration polarization layer to thin through increased back transport velocity of particles. So, it can remove even dissolved constituents effectively. Therefore, As (V) ions such as H2AsO4- and HAsO42- can be removed. The concentration of As (V) ions decreased from 50 μg/L to below 10 μg/L and condensation factor in recirculating water increased up to 7 times by using NF membrane equipped with VSEP.

Download Full-text