scholarly journals Enhancing arsenic removal from groundwater at household level with naturally occurring iron

2016 ◽  
Vol 11 (3) ◽  
pp. 486 ◽  
Author(s):  
Anitha Kumari Sharma ◽  
Sabrina Sorlini ◽  
Barbara Marianna Crotti ◽  
Maria Cristina Collivignarelli ◽  
Jens Christian Tjell ◽  
...  
Keyword(s):  
Small Volume ◽  
Arsenic Removal ◽  
Low Cost ◽  
Buffering Capacity ◽  
Basic Solution ◽  
Oxidizing Agent ◽  
Household Level ◽  
Naturally Occurring ◽  
Pale Pink ◽  
High Concentrations

A supply of drinking water low in Arsenic (As) prevents arsenic poisoning. The presence of high concentrations of iron (Fe) in groundwater under the alluvial plains of the large rivers in Southeast Asia is a prerequisite for the simple removal of As. This study investigated the mechanisms and possibilities for enhancing As removal with naturally occurring Fe in a reliable, low cost and sustainable way. The results of the study show that As removal with Fe is greatly enhanced by the addition of an oxidizing agent (preferably KMnO4) immediately after the pumping of groundwater. Further enhancement of As removal in the presence of Fe can be achieved by adding a small volume of a concentrated basic solution of MnO4- and AlO2-, which has a combined oxidation, coagulation and buffering capacity. Best results were obtained when this solution was mixed with the groundwater immediately after its pumping until a pale pink color appeared. Maximum required reaction time was 10 minutes and subsequent filtration of the water was able to reduce the As concentration to near zero. Concentrations of MnO4- and AlO2- can be varied in the solution to achieve sufficient As removal to suit different Fe/As ratios and the presence of interfering co-occurring anions.

A low cost technique of arsenic removal from drinking water by coagulation using ferric chloride salt and alum

2002 ◽  
Vol 2 (2) ◽  
pp. 281-288 ◽  
Author(s):  
M.M.T. Khan ◽  
K. Yamamoto ◽  
M.F. Ahmed
Keyword(s):  
Removal Efficiency ◽  
Ferric Chloride ◽  
Arsenic Removal ◽  
Low Cost ◽  
Chloride Salt ◽  
Oxidizing Agent ◽  
Bleaching Powder ◽  
Treatment Processes ◽  
Intensive Investigation ◽  
Removal Of Arsenic

A variety of treatment processes have been used for arsenic removal from water. In a laboratory study using natural (tubewell) water, ferric chloride salt and alum were used, which are the most studied and widely used flocculents in water treatment due to their low price, comfortable availability and low risk usability. The solubility of arsenate(III) is much more than arsenite(V). Arsenate(III) was converted into arsenite(V) by proper oxidation using bleaching powder as an oxidizing agent before coagulation. The concentrations of ferric chloride salt and alum dose were varied from 10 mg/l to 200 mg/l, and pH was varied from 4 to 9. After intensive investigation, it was found that at pH 7 and for 100 mg/l to 125 mg/l dose of alum, the removal efficiency of arsenic and iron were around 82 to 86% and 92 to 95% respectively. Again, the optimum removal of arsenic and iron were around 90 to 93% and 97 to 100% respectively at pH 7 for 200 mg/l of ferric chloride salt. This research was carried out not only to observe the removal efficiency of arsenic, but also iron. Because most of the tubewells in Bangladesh, sometimes, contain higher amount of iron.

scholarly journals Adsorption Studies for Arsenic Removal Using ActivatedMoringa oleifera

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
T. Sumathi ◽  
G. Alagumuthu
Keyword(s):  
Experimental Data ◽  
Langmuir Isotherm ◽  
Moringa Oleifera ◽  
Arsenic Removal ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Cost Effective ◽  
Batch Experiments ◽  
Household Level ◽  
Kinetics Studies

A new low cost adsorbent, activatedMoringa oleiferahas been developed for aqueous arsenic removal. Batch experiments were revealed that As removal was up to 71.3% using activatedMoringa oleifera. Kinetics studies revealed that Langmuir isotherm was followed with a better correlation than the Freundlich isotherm. The thermodynamic parameters such asΔH,ΔS, andΔGwere computed from the experimental data. These values show that the adsorption is endothermic and spontaneous in nature. Thus, this recently developed cost-effective novel biosorbent, activatedMoringa oleiferacan be used as household level to mitigate the arsenic problem.

Efficient low-cost magnetic composite based on eucalyptus wood biochar for arsenic removal from groundwater

2021 ◽  
Vol 14 ◽  
pp. 100585
Author(s):  
Amalia Lara Bursztyn Fuentes ◽  
Facundo Barraqué ◽  
Roberto Carlos Mercader ◽  
Alberto Néstor Scian ◽  
María Luciana Montes
Keyword(s):  
Arsenic Removal ◽  
Low Cost ◽  
Magnetic Composite ◽  
Eucalyptus Wood

scholarly journals Synthesis of Exosome-Based Fluorescent Gold Nanoclusters for Cellular Imaging Applications

2021 ◽  
Vol 22 (9) ◽  
pp. 4433
Author(s):  
Eun Sung Lee ◽  
Byung Seok Cha ◽  
Seokjoon Kim ◽  
Ki Soo Park
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Stokes Shift ◽  
Gold Nanoclusters ◽  
Human Colon ◽  
Cellular Imaging ◽  
Metal Nanoclusters ◽  
Human Colon Cancer ◽  
X Ray ◽  
High Concentrations

In recent years, fluorescent metal nanoclusters have been used to develop bioimaging and sensing technology. Notably, protein-templated fluorescent gold nanoclusters (AuNCs) are attracting interest due to their excellent fluorescence properties and biocompatibility. Herein, we used an exosome template to synthesize AuNCs in an eco-friendly manner that required neither harsh conditions nor toxic chemicals. Specifically, we used a neutral (pH 7) and alkaline (pH 11.5) pH to synthesize two different exosome-based AuNCs (exo-AuNCs) with independent blue and red emission. Using field-emission scanning electron microscopy, energy dispersive X-ray microanalysis, nanoparticle tracking analysis, and X-ray photoelectron spectroscopy, we demonstrated that AuNCs were successfully formed in the exosomes. Red-emitting exo-AuNCs were found to have a larger Stokes shift and a stronger fluorescence intensity than the blue-emitting exo-AuNCs. Both exo-AuNCs were compatible with MCF-7 (human breast cancer), HeLa (human cervical cancer), and HT29 (human colon cancer) cells, although blue-emitting exo-AuNCs were cytotoxic at high concentrations (≥5 mg/mL). Red-emitting exo-AuNCs successfully stained the nucleus and were compatible with membrane-staining dyes. This is the first study to use exosomes to synthesize fluorescent nanomaterials for cellular imaging applications. As exosomes are naturally produced via secretion from almost all types of cell, the proposed method could serve as a strategy for low-cost production of versatile nanomaterials.

scholarly journals Arsenic Removal by Advanced Electrocoagulation Processes: The Role of Oxidants Generated and Kinetic Modeling

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 928
Author(s):  
Micah Flor V. Montefalcon ◽  
Meliton R. Chiong ◽  
Augustus C. Resurreccion ◽  
Sergi Garcia-Segura ◽  
Joey D. Ocon
Keyword(s):  
Kinetic Modeling ◽  
Arsenic Removal ◽  
Fold Increase ◽  
Electrochemical Treatment ◽  
Promising Alternative ◽  
Iron Electrodes ◽  
Removal Capacity ◽  
Naturally Occurring ◽  
Treatment Technologies

Arsenic (As) is a naturally occurring element in the environment that poses significant risks to human health. Several treatment technologies have been successfully used in the treatment of As-contaminated waters. However, limited literature has explored advanced electrocoagulation (EC) processes for As removal. The present study evaluates the As removal performance of electrocoagulation, electrochemical peroxidation (ECP), and photo-assisted electrochemical peroxidation (PECP) technologies at circumneutral pH using electroactive iron electrodes. The influence of As speciation and the role of oxidants in As removal were investigated. We have identified the ECP process to be a promising alternative for the conventional EC with around 4-fold increase in arsenic removal capacity at a competitive cost of 0.0060 $/m3. Results also indicated that the rate of As(III) oxidation at the outset of electrochemical treatment dictates the extent of As removal. Both ECP and PECP processes reached greater than 96% As(III) conversion at 1 C/L and achieved 86% and 96% As removal at 5 C/L, respectively. Finally, the mechanism of As(III) oxidation was evaluated, and results showed that Fe(IV) is the intermediate oxidant generated in advanced EC processes, and the contribution of •OH brought by UV irradiation is insignificant.

scholarly journals Mendelian randomisation for psychiatry: how does it work, and what can it tell us?

2021 ◽  
Author(s):  
Robyn E. Wootton ◽  
Hannah J. Jones ◽  
Hannah M. Sallis
Keyword(s):  
Risk Factors ◽  
Mental Illness ◽  
Risk Factor ◽  
Low Cost ◽  
Sensitivity Analyses ◽  
Mendelian Randomisation ◽  
Naturally Occurring ◽  
Complementary Approach ◽  
Randomised Control Trials ◽  
Successful Prevention

AbstractThe successful prevention of mental illness relies upon the identification of causal, modifiable risk factors. However, observational evidence exploring such risk factors often produces contradictory results and randomised control trials are often expensive, time-consuming or unethical to conduct. Mendelian randomisation (MR) is a complementary approach that uses naturally occurring genetic variation to identify possible causal effects between a risk factor and an outcome in a time-efficient and low-cost manner. MR utilises genetic variants as instrumental variables for the risk factor of interest. MR studies are becoming more frequent in the field of psychiatry, warranting a reflection upon both the possibilities and the pitfalls. In this Perspective, we consider several limitations of the MR method that are of particular relevance to psychiatry. We also present new MR methods that have exciting applications to questions of mental illness. While we believe that MR can make an important contribution to the field of psychiatry, we also wish to emphasise the importance of clear causal questions, thorough sensitivity analyses, and triangulation with other forms of evidence.

scholarly journals Desensitization Contributes to the Synaptic Response of Gain-of-Function Mutants of the Muscle Nicotinic Receptor

2006 ◽  
Vol 128 (5) ◽  
pp. 615-627 ◽  
Author(s):  
Sergio Elenes ◽  
Ying Ni ◽  
Gisela D. Cymes ◽  
Claudio Grosman
Keyword(s):  
Nicotinic Receptor ◽  
Dissociation Rate ◽  
Gain Of Function ◽  
Naturally Occurring ◽  
Channel Opening ◽  
Speed Up ◽  
High Concentrations ◽  
Dissociation Rate Constants ◽  
Kinetics Of ◽  
Peak Value

Although the muscle nicotinic receptor (AChR) desensitizes almost completely in the steady presence of high concentrations of acetylcholine (ACh), it is well established that AChRs do not accumulate in desensitized states under normal physiological conditions of neurotransmitter release and clearance. Quantitative considerations in the framework of plausible kinetic schemes, however, lead us to predict that mutations that speed up channel opening, slow down channel closure, and/or slow down the dissociation of neurotransmitter (i.e., gain-of-function mutations) increase the extent to which AChRs desensitize upon ACh removal. In this paper, we confirm this prediction by applying high-frequency trains of brief (∼1 ms) ACh pulses to outside-out membrane patches expressing either lab-engineered or naturally occurring (disease-causing) gain-of-function mutants. Entry into desensitization was evident in our experiments as a frequency-dependent depression in the peak value of succesive macroscopic current responses, in a manner that is remarkably consistent with the theoretical expectation. We conclude that the comparatively small depression of the macroscopic currents observed upon repetitive stimulation of the wild-type AChR is due, not to desensitization being exceedingly slow but, rather, to the particular balance between gating, entry into desensitization, and ACh dissociation rate constants. Disruption of this fine balance by, for example, mutations can lead to enhanced desensitization even if the kinetics of entry into, and recovery from, desensitization themselves are not affected. It follows that accounting for the (usually overlooked) desensitization phenomenon is essential for the correct interpretation of mutagenesis-driven structure–function relationships and for the understanding of pathological synaptic transmission at the vertebrate neuromuscular junction.

NUTRITION OF A COBALAMIN-REQUIRING SOIL BACTERIUM

1957 ◽  
Vol 3 (2) ◽  
pp. 329-334 ◽  
Author(s):  
Milton K. Goldberg ◽  
S. H. Hutner ◽  
J. E. Ford
Keyword(s):  
Growth Response ◽  
Soil Bacterium ◽  
Intrinsic Activity ◽  
Vitamin B ◽  
Factor B ◽  
Naturally Occurring ◽  
High Concentrations

The pattern of the vitamin B12 requirement of a soil bacterium "Lochhead 38" (provisionally assigned to Arthrobacter) resembled that of the protozoan Ochromonas malhamensis and of higher animals. Of the naturally-occurring B12-vitamins, cyanocobalamin and vitamin B12III are active. Pseudovitamin B12 and Factor A have very little or no intrinsic activity, and when present in relatively high concentrations both compounds depress the rate of the growth response to limiting cyanocobalamin. Factor B, the porphyrin-like nucleus of the vitamin B12 molecule without the nucleotide, is inactive, as are also methionine and deoxyribosides. A disadvantage in the use of Lochhead 38 for assay purposes is that in vitamin-B12-dehcient cultures the organisms flocculate.

Point-of-entry adsorbers for the removal of fumigants

1995 ◽  
Vol 22 (1) ◽  
pp. 106-120
Author(s):  
Roberto M. Narbaitz ◽  
Frances Z. Parsons ◽  
Tsong-Yih Tzeng
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Low Cost ◽  
Scale Up ◽  
Extensive Literature ◽  
Limited Data ◽  
Ethylene Dibromide ◽  
Point Of Entry ◽  
Naturally Occurring ◽  
Adsorption Data

Point-of-entry systems with granular activated carbon filters have been used extensively to provide safe water to rural homes with wells contaminated with synthetic organic chemicals. Because of the low cost of these systems, their design is generally based on the equilibrium column model, the isotherm data from the literature, and a scale-up factor. This paper analyzes the necessary scale-up factors for point-of-entry adsorbers based on fumigant adsorption data gathered through an extensive literature review. The fumigants evaluated are 1,2-dichloropropane, 1,2-dibromo-3-chloropropane, and ethylene dibromide. It was impossible to thoroughly assess the scale-up factors for 1,2-dichloropropane because of the limited data. Column data for the other two fumigants were sufficient to generate column loading lines, which can be used directly without resorting to scale-up factors. Column data showed that the scale-up factors are greatly affected by competitive adsorption with the naturally occurring background organic matter and by preloading of these organic matter. As these phenomena are not well understood, it is presently impossible to accurately predict the appropriate scale-up factors. A recommended design approach is outlined. Key words: adsorption, activated carbon, fumigants, point-of-entry.

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