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2022 ◽  
Vol 179 ◽  
pp. 106135
Author(s):  
Yunkun Qian ◽  
Yanan Chen ◽  
David Hanigan ◽  
Yijun Shi ◽  
Sainan Sun ◽  
...  

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Dušan Oráč ◽  
Jakub Klimko ◽  
Dušan Klein ◽  
Jana Pirošková ◽  
Pavol Liptai ◽  
...  

Copper anode furnace dust is waste by-product of secondary copper production containing zinc, lead, copper, tin, iron and many other elements. Hydrometallurgical Copper Anode Furnace dust recycling method was studied theoretically by thermodynamic calculations and the proposed method was verified experimentally on a laboratory scale. The optimum condition for leaching of zinc from dust was identified to be an ambient leaching temperature, a liquid/solid ratio of 10 and H2SO4 concentration of 1 mol/L. A maximum of 98.85% of zinc was leached under the optimum experimental conditions. In the leaching step, 99.7% of lead in the form of insoluble PbSO4 was separated from the other leached metals. Solution refining was done by combination of pH adjustment and zinc powder cementation. Tin was precipitated from solution by pH adjustment to 3. Iron was precipitated out of solution after pH adjustment to 4 with efficiency 98.54%. Copper was selectively cemented out of solution (99.96%) by zinc powder. Zinc was precipitated out of solution by addition of Na2CO3 with efficiency of 97.31%. ZnO as final product was obtained by calcination of zinc carbonates.


Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 958
Author(s):  
Paula G. Santos ◽  
Cíntia M. Scherer ◽  
Adriano G. Fisch ◽  
Marco Antônio S. Rodrigues

In the research reported in this paper, membrane distillation was employed to recover water from a concentrated saline petrochemical effluent. According to the results, the use of membrane distillation is technically feasible when pre-treatments are employed to mitigate fouling. A mathematical model was used to evaluate the fouling mechanism, showing that the deposition of particulate and precipitated material occurred in all tests; however, the fouling dynamic depends on the pre-treatment employed (filtration, or filtration associated with a pH adjustment). The deposit layer formed by particles is not cohesive, allowing its entrainment to the bulk flow. The precipitate fouling showed a minimal tendency to entrainment. Also, precipitate fouling served as a coupling agent among adjacent particles, increasing the fouling layer cohesion.


Author(s):  
Florencia A. Angelini ◽  
Eduardo R. Pegels ◽  
Marina I. Quiroga

The spread of carbapenemase-producing gram-negative bacilli is a global public health problem. Several authors have proposed phenotypic assays to presumptively detect these enzymes applicable to low and medium complexity laboratories. In the present study, we have developed and compared different phenotypic techniques using strains genetically identified as carbapenemase-producing. All the tested methods detected the presence of carbapenemases. The carbapenem inactivation method (MIC) and the modified carbapenem inactivation method with and without EDTA (mMIC-eMIC) were the simplest and easiest to interpret but their disadvantage was on the time required to obtain results. The direct Carba NP and Carba-Blue colourimetric methods were the fastest but they depend on reagent preparation and accurate pH adjustment of the solutions. Synergy methods with EDTA discs, boronic acid and the Triton Hodge Test (THT) require technical expertise to evaluate true synergism. Whereas, the Disk Carbapenemase Test (DCT) was the method that presented the greatest technical difficulties.


2021 ◽  
pp. 126605
Author(s):  
Gwon Woo Park ◽  
Myounghoon Moon ◽  
Jeong-Ho Park ◽  
Jae-Hwan Jo ◽  
Hyouck Ju Kim ◽  
...  

2021 ◽  
Vol 63 (11) ◽  
pp. 29-34
Author(s):  
Thanh Dam Nguyen ◽  
◽  
Thi Phuc Nguyen ◽  
Minh Tuan Vu ◽  
◽  
...  

pH buffers of weak organic acids and bases are essential in capillary electrophoresis (CE) analyses, primarily when contactless conductivity detectors (C4D) are used. However, the preparation of a buffer with a known concentration of one component for use as a background electrolyte (BGE) in CE-C4D usually requires a pH adjustment to the desired value and an approximate calculation to estimate the concentration of the second component. This study developed software that allowed determining the concentration of one component when knowing the concentration of another component and the pH of the solution, taking into account the influence of ionic strength. The software was built in C# language with Windows Form interface on Microsoft Visual Studio. With the concentrations calculated from the developed software, the differences (|ΔpH|) between pH values of the obtained BGEs in practice and the desired values were smaller than 0.07, corresponding to the errors of less than 2%.


2021 ◽  
Author(s):  
◽  
Nyiko Charity Mabasa

Water scarcity in South Africa, and globally, presents challenges for industries. It is imperative to develop responsible water use, such as recycling and reusing wastewater from food processing industries such as breweries. The Ibhayi Brewery (SAB Ltd) employs a combination of sustainable treatment processes that include anaerobic digestion (AD), primary facultative ponds (PFP), high rate algal ponds (HRAP) and constructed wetlands (CW) to treat brewery effluent on an experimental scale. The constituent concentrations of these experimentally treated effluents are within the ranges prescribed by local regulations to allow for potential downstream use in agriculture and aquaculture. However, the sodium content in this treated effluent, which originates from upstream cleaning agents and pH control at the onsite effluent treatment facility, is a constraint to the downstream use of brewery effluent. This study addresses the salt problem, by investigating the potential of either reducing/eliminating salt addition at source, or developing alternative techniques for downstream agriculture to mitigate the effects of salt accumulation caused by irrigation with brewery effluent. Four salt-tolerant test crops; Swiss chard (Beta vulgaris), saltbush (Atriplex nummularia), Salicornia meyeriana and sorghum (Sorghum bicolor), grew efficiently in brewery effluent irrigated soils but did not stop sodium accumulation in the growth medium. Swiss chard had the best growth with a wet biomass accumulation of 8,173 g m-2, due to the plant’s ability to tolerate saline conditions and continuous cropping. Crop rotation, to limit effects of nutrient depletion in soil, had no significant effect on plant growth suggesting soils were adequately able to provide micro-nutrients in the short-term. Prolonged irrigation with brewery effluent can lead to sodium accumulation in the soil, which was successfully controlled through the addition of soil amendments (gypsum and Trichoderma cultures). These reduced soil sodium from a potentially limiting level of 1,398 mg L-1 to the acceptable levels of 240 mg L-1 and 353 mg L-1 respectively, mainly through leaching. However only Trichoderma improved Swiss chard production to 11,238 g m-2. While crop rotation in this work did not contribute to mitigating the problem of salt accumulation, soil amended with Trichoderma appears to be a potential solution when brewery effluent is reused in agriculture. In an alternative to soil cultivation, CWs were trialled with no significant differences in the sodium concentration of brewery effluent treated along a 15 m lateral flow CW, which could be attributed to evapotranspiration. This was notably accompanied by a desirable 95.21% decrease in ammonia from inlet to outlet resulting in significant improvement in water quality for reuse in aquaculture where ammonia levels are important limiting constraints. While CWs remain a suitable brewery effluent treatment solution, this technology requires additional modelling and optimisation in order to mitigate the problem of salt accumulation in the reuse of treated brewery effluent in agriculture and aquaculture. This research demonstrates the baseline information for such modelling and optimisation. African catfish (Clarias gariepinus) grew in CW treated brewery effluent; however, this growth was moderate at 0.92% bw day-1, whereas Mozambique tilapia (Oreochromis mossambicus) were shown to be unsuited to growth in this system and lost weight with an average specific growth rate (SGR) of -0.98% bw day-1; and both fish species presenting with health related concerns. Hardy fish species such as African catfish can be cultured in brewery effluent, but with risk involved. This was a preliminary study to develop parameters for future dimensional analysis modelling to allow optimisation of the CW, based on nutrient removal rates obtained which will allow for improved downstream aquaculture by reducing or eliminating risks presented in this study. This work has also contributed to a foundation for the development of guidelines that use a risk-based approach for water use in aquaculture. Alternatives to the current in place cleaning agents were considered to mitigate the effects of salt accumulation. Sodium is introduced into the effluent via the use of sodium hydroxide and sodium chlorite for cleaning and disinfection in the brewery, as well as through effluent pH adjustment in the AD plant. The widespread use of outdated legacy cleaning systems and pH adjustment regimes is entrenched in the brewery standard operating procedures (SOP). A cost-benefit analysis (CBA) demonstrated that a change of cleaning and disinfecting regimes to hydrogen peroxide in the brewery, and magnesium hydroxide pH adjustment in the effluent treatment plant addresses the sodium issue upstream in the brewery practically eliminating sodium from the effluent. In addition, a life cycle analysis (LCA) was carried out to assess the environmental impacts associated with the alternative cleaning and pH adjustment scenarios. The LCA showed that electricity consumption during use phase of the chemicals for respective purposes, as well as their production activities were major contributors to the significant environmental impact categories that were assessed. The cleaning scenario employing the use of hydrogen peroxide for both cleaning and disinfection was found to be the most environmentally sustainable. This was attributed to the reduced number of chemicals used compared to the other cleaning scenarios. Dolomitic lime was the pH adjustment alternative with the lowest average environmental impact; but, however, had a higher impact on freshwater eutrophication which is of major concern if the effluent will be reused for irrigation. Magnesium hydroxide was therefore considered to be the better option as a sodium hydroxide alternative for pH adjustment. This mitigates salt accumulation, making treated brewery effluent suitable for reuse in high value downstream agriculture and aquaculture, while employing more environmentally sustainable technologies. Notably, this converts brewery effluent from a financial liability to Ibhayi Brewery, into a product containing water and nutrients that generate income, improve food security, and can create employment in downstream agriculture and aquaculture in a sustainable manner.


2021 ◽  
Vol 11 (3) ◽  
pp. 19-27
Author(s):  
Ali Salim Abd Al-Hussein

The aim of this paper is to explain the advantages of using sulfuric acid in Qarmat Ali water treatment plant belong to Basrah Oil Company, which produces water for injection into the Rumaila reservoirs. Sulfuric acid is a strong acid providing rapid and effective pH reduction. Maintaining the coagulation pH within the optimum value (6.4) by inject specific value of sulfuric acid to RAW water enhances the clarification performances by reducing the clarified water turbidity to minimum value (5.1). It was preferable for  operating at a pH below the saturation pH to prevent the precipitation of minerals such as calcium carbonate which are contributing to blocking the surface filters installed downstream (auto back wash filters) and The clarifiers that cause increased the feed from 500 MBD  to 1000 MBD. With a fast and rapid dissociation in Water, Sulfuric acid is an effective and practical way to lower the pH on Qarmat Ali plant which producing in excess of 1,000MBD of export water.


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