The Removal of Arsenic from Process Solutions: Theory and Industrial Practice

Author(s):  
Bryn Harris
2016 ◽  
Vol 15 (8) ◽  
pp. 1721-1728
Author(s):  
Pavel Janos ◽  
Alexandra Eletskaya ◽  
Vera Pilarova
Keyword(s):  

2019 ◽  
Vol 18 (12) ◽  
pp. 2655-2662
Author(s):  
Yongliang Wang ◽  
Peiwei Han ◽  
Yonggang Lu ◽  
Li Xiao ◽  
Yingchao Du ◽  
...  

2003 ◽  
Vol 3 (5-6) ◽  
pp. 303-310 ◽  
Author(s):  
S.-H. Yi ◽  
S. Ahmed ◽  
Y. Watanabe ◽  
K. Watari

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.


1999 ◽  
Vol 40 (11-12) ◽  
pp. 201-206
Author(s):  
I. Reilama ◽  
N. Ilomäki

Oy Metsä-Botnia Ab's Kaskinen mill produces ECF and TCF bleached softwood and hardwood pulp on a single continuous production line. Production capacity has been raised from 250,000 tonnes to 420,000 tonnes a year after the commission in 1977. The basic process solutions date mainly from the 1970s. However, process technology has been gradually modernised. With systematic and well-timed process development investments the mill has remained competitive and among frontrunners in terms of environmental protection. Today, Kaskinen represent the best available technology (BAT) applicable to old mills. Effluent loading in general and nutrient emissions in particular has diminished during the development projects of the mill. Comparison to other mills shows that as far as effluent emissions are concerned, Kaskinen is one of the best pulp mills in Finland and Scandinavia. In this presentation, Kaskinen is also compared to Metsä-Rauma, the first greenfield TCF mill in the world, which was started up in 1996. Kaskinen's pioneering work on TCF technology was used as a basis for process solutions in the Rauma greenfield project.


2019 ◽  
Author(s):  
Joanne U. Angai ◽  
◽  
Carol J. Ptacek ◽  
Brent R. Verbuyst ◽  
Jeff G. Bain ◽  
...  
Keyword(s):  

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 250
Author(s):  
Jiří Hájek ◽  
Zaneta Dlouha ◽  
Vojtěch Průcha

This article is a response to the state of the art in monitoring the cooling capacity of quenching oils in industrial practice. Very often, a hardening shop requires a report with data on the cooling process for a particular quenching oil. However, the interpretation of the data can be rather difficult. The main goal of our work was to compare various criteria used for evaluating quenching oils. Those of which prove essential for operation in tempering plants would then be introduced into practice. Furthermore, the article describes monitoring the changes in the properties of a quenching oil used in a hardening shop, the effects of quenching oil temperature on its cooling capacity and the impact of the water content on certain cooling parameters of selected oils. Cooling curves were measured (including cooling rates and the time to reach relevant temperatures) according to ISO 9950. The hardening power of the oil and the area below the cooling rate curve as a function of temperature (amount of heat removed in the nose region of the Continuous cooling transformation - CCT curve) were calculated. V-values based on the work of Tamura, reflecting the steel type and its CCT curve, were calculated as well. All the data were compared against the hardness and microstructure on a section through a cylinder made of EN C35 steel cooled in the particular oil. Based on the results, criteria are recommended for assessing the suitability of a quenching oil for a specific steel grade and product size. The quenching oils used in the experiment were Houghto Quench C120, Paramo TK 22, Paramo TK 46, CS Noro MO 46 and Durixol W72.


Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1827
Author(s):  
Piotr Cofta ◽  
Kostas Karatzas ◽  
Cezary Orłowski

The growing popularity of inexpensive IoT (Internet of Things) sensor networks makes their uncertainty an important aspect of their adoption. The uncertainty determines their fitness for purpose, their perceived quality and the usefulness of information they provide. Nevertheless, neither the theory nor the industrial practice of uncertainty offer a coherent answer on how to address uncertainty of networks of this type and their components. The primary objective of this paper is to facilitate the discussion of what progress should be made regarding the theory and the practice of uncertainty of IoT sensor networks to satisfy current needs. This paper provides a structured overview of uncertainty, specifically focusing on IoT sensor networks. It positions IoT sensor networks as contrasted with professional measurement and control networks and presents their conceptual sociotechnical reference model. The reference model advises on the taxonomy of uncertainty proposed in this paper that demonstrates semantic differences between various views on uncertainty. This model also allows for identifying key challenges that should be addressed to improve the theory and practice of uncertainty in IoT sensor networks.


2021 ◽  
Vol 49 (4) ◽  
pp. 2000233
Author(s):  
Trung Huu Bui ◽  
Van Sy Pham ◽  
Nguyen Thanh‐Nho ◽  
Quoc An Trieu

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2247
Author(s):  
Mirosław Słowiński ◽  
Joanna Miazek ◽  
Krzysztof Dasiewicz ◽  
Marta Chmiel

A beneficial aspect of the use of fiber preparations in the meat industry is the improvement of some quality characteristics of meat products. However, the preparation added in the amount of 3 or 6% may affect their color. The effect of the addition of barley, wheat and oat fiber preparations with different fiber lengths, in quantities allowing the product to be indicated as “high in fiber” or “source of fiber”, to pasteurized or sterilized medium-grounded canned meat products on their color, was determined. In the obtained canned meat products, the basic chemical composition and the L*, a* and b*, C* (Chroma) and h* (hue angle) color components were determined. The addition of the barley fiber preparation BG 300 to the model canned meat products caused a significant (p ≤ 0.05) darkening and an increase in the proportion of yellow color. In an industrial practice, this may result in poorer consumer acceptance of the meat product. Fiber length of wheat and barley fiber had no effect on the color components of products. The 6% addition of the wheat fiber preparations WF 200R and WF 600R or the oat fiber preparations HF 200 and HF 600 caused an apparent lightening of their color (ΔE > 2) compared to the control products.


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