scholarly journals Unusually High Concentration of Alkyl Ammonium Hydroxide in the Cation–Hydroxide–Water Coadsorbed Layer on Pt

2019 ◽  
Vol 12 (1) ◽  
pp. 1825-1831 ◽  
Author(s):  
Joseph H. Dumont ◽  
André J. Spears ◽  
Rex P. Hjelm ◽  
Marilyn Hawley ◽  
Sandip Maurya ◽  
...  
2021 ◽  
Vol 22 (2) ◽  
pp. 215-221
Author(s):  
Luluk Edahwati ◽  
Sutiyono ◽  
Rizqi Rendri Anggriawan

ABSTRACT Struvite, also known as magnesium ammonium phosphate hexahydrate, is a white crystal with a chemical formula magnesium ammonium phosphate hexahydrate (MgNH4PO4.6H2O). Because of its phosphate content, struvite can be utilized as a fertilizer. Tempeh industrial effluent contains a high concentration of PO4, making it a possible struvite fertilizer producing material. The formation of struvite fertilizer is carried out by the aeration process. This process is able to increase the pH and homogeneity of the solution. The solution of Magnesium Ammonium Phosphate (MAP) is prepared by reacting tempeh industrial wasterwater, Magnesium Chloride (MgCl2), and Ammonium Hydroxide (NH4OH). The MAP ratios used are 1:1:1 and 3:1:1. The temperature was set at 30 °C and pH 9, the airflow rate was carried out at a rate of 0.25 - 1.25 liters per minute. Struvite crystals were analyzed using X-ray Fluorescence (XRF) and Scanning Electron Microscope (SEM). The best struvite fertilizer content is magnesium by 40.3% and phosphorus by 43.9% at an air flow rate of 1.25 liters per minute and a ratio of 3:1:1. Further development can be done by applying struvite fertilizers to plants.  Keywords: aeration, crystallization, tempeh industrial wastewater, struvite   ABSTRAK Struvite adalah kristal putih yang secara kimiawi dikenal sebagai magnesium amonium fosfat heksahidrat (MgNH4PO4.6H2O). Struvite dapat dimanfaatkan menjadi pupuk karena kandungan fosfat (PO4) di dalamnya. Limbah cair industri tempe memiliki kandungan PO4 yang cukup tinggi, menjadikan limbah cair industri tempe adalah bahan pembentuk pupuk struvite yang potensial. Pembentukan pupuk struvite dilakukan dengan proses aerasi. Proses ini mampu meningkatkan pH dan homogenitas dari larutan. Larutan MAP (Magnesium Amonium Fosfat) dibuat dengan cara mereaksikan limbah cair industri tempe, Magnesium Klorida (MgCl2), dan Amonium Hidroksida (NH4OH). Rasio MAP yang digunakan adalah 1:1:1 dan 3:1:1. Temperatur ditetapkan sebesar 30°C dan pH 9, laju alir udara dilakukan dengan laju 0,25 - 1,25 liter per menit. Kristal struvite dianalisis menggunakan Floresensi sinar-X (XRF) dan Mikroskop Pemindai Elektron (SEM). Kandungan pupuk struvite terbaik adalah magnesium sebesar 40,3% dan fosfor sebesar 43,9% pada konsentrasi 3:1:1 dan laju alir udara 1,25 liter per menit. Pengembangan lebih lanjut dapat dilakukan dengan mengaplikasikan pupuk struvite ke tanaman. Kata Kunci: aerasi, kristalisasi, limbah cair industri tempe, struvite


2021 ◽  
Vol 13 (18) ◽  
pp. 10014
Author(s):  
Ameera F. Mohammad ◽  
Ali H. Al-Marzouqi ◽  
Muftah H. El-Naas ◽  
Bart Van der Bruggen ◽  
Mohamed H. Al-Marzouqi

This paper describes a new method for the recovery of high-concentration ammonia from water in the form of ammonium chloride, ammonium hydroxide and ammonium carbonate. The method was applied to the Solvay process, in which sodium bicarbonate is produced through the reaction of ammoniated brine and CO2 gas. The Solvay effluent contains ammonia in the form of soluble ammonium chloride. The proposed method is based on the recovery of ammonia using a high-alkalinity reactant, calcium oxide (CaO), in a closed electrocoagulation cell operating at a specific current density. The recovered ammonia is collected as a gas within a closed cell containing deionized (DI) water at room temperature. Afterwards, the collected solution (DI water–NH3 gas) is concentrated through a separate process, and is then reused in the Solvay process and other applications. The electrocoagulation process is applied to the treatment cell using aluminum electrodes and a current density of 5–15 mA/cm2. After 7 h of treatment using the electrocoagulation cell, a high reduction of the ammonia concentration—99%—was realized after ~9 h of the electrochemical treatment. The initial ammonia concentration in a Solvay effluent of 13,700 mg/L N was decreased to 190 mg/L N. Furthermore, an ammonia recovery of 77.1% in the form of ammonium hydroxide was achieved. Generally, this process, which starts at room temperature, can result in an energy reduction of 80%—from 7.8 to 2.3 kWh/kg NH3—compared to conventional processes, which entail heating the Solvay effluents to 160 °C. The proposed system and method were found to be suitable for the recovery of ammonia from ammoniated water, and can be utilized for the treatment of landfill leachate, and municipal and industrial wastewater.


Author(s):  
Daniel C. Pease

A previous study demonstrated that tissue could be successfully infiltrated with 50% glutaraldehyde, and then subsequently polymerized with urea to create an embedment which retained cytomembrane lipids in sectioned material. As a result, the 180-190 Å periodicity characteristic of fresh, mammalian myelin was preserved in sections, as was a brilliant birefringence, and the capacity to bind OsO4 vapor in the hydrophobic bilayers. An associated (unpublished) study, carried out in co-operation with Drs. C.K. Akers and D.F. Parsons, demonstrated that the high concentration of glutaraldehyde (and urea) did not significantly alter the X-ray diffraction pattern of aldehyde-fixed, myelin. Thus, by itself, 50% glutaraldehyde has little effect upon cytomembrane systems and can be used with confidence for the first stages of dehydration.


Author(s):  
Glenn M. Cohen ◽  
Radharaman Ray

Retinal,cell aggregates develop in culture in a pattern similar to the in ovo retina, forming neurites first and then synapses. In the present study, we continuously exposed chick retinal cell aggregates to a high concentration (1 mM) of carbamylcholine (carbachol), an acetylcholine (ACh) analog that resists hydrolysis by acetylcholinesterase (AChE). This situation is similar to organophosphorus anticholinesterase poisoning in which the ACh level is elevated at synaptic junctions due to inhibition of AChE, Our objective was to determine whether continuous carbachol exposure either damaged cholino- ceptive neurites, cell bodies, and synaptic elements of the aggregates or influenced (hastened or retarded) their development.The retinal tissue was isolated aseptically from 11 day embryonic White Leghorn chicks and then enzymatically (trypsin) and mechanically (trituration) dissociated into single cells. After washing the cells by repeated suspension and low (about 200 x G) centrifugation twice, aggregate cell cultures (about l0 cells/culture) were initiated in 1.5 ml medium (BME, GIBCO) in 35 mm sterile culture dishes and maintained as experimental (containing 10-3 M carbachol) and control specimens.


Author(s):  
James Cronshaw

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.


Author(s):  
R.A. Herring

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.


2020 ◽  
Vol 477 (15) ◽  
pp. 2921-2934
Author(s):  
Rodrigo D. Requião ◽  
Géssica C. Barros ◽  
Tatiana Domitrovic ◽  
Fernando L. Palhano

Protein segments with a high concentration of positively charged amino acid residues are often used in reporter constructs designed to activate ribosomal mRNA/protein decay pathways, such as those involving nonstop mRNA decay (NSD), no-go mRNA decay (NGD) and the ribosome quality control (RQC) complex. It has been proposed that the electrostatic interaction of the positively charged nascent peptide with the negatively charged ribosomal exit tunnel leads to translation arrest. When stalled long enough, the translation process is terminated with the degradation of the transcript and an incomplete protein. Although early experiments made a strong argument for this mechanism, other features associated with positively charged reporters, such as codon bias and mRNA and protein structure, have emerged as potent inducers of ribosome stalling. We carefully reviewed the published data on the protein and mRNA expression of artificial constructs with diverse compositions as assessed in different organisms. We concluded that, although polybasic sequences generally lead to lower translation efficiency, it appears that an aggravating factor, such as a nonoptimal codon composition, is necessary to cause translation termination events.


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