scholarly journals Removal of boron from aqueous solution using cryptocrystalline magnesite

2016 ◽  
Vol 7 (2) ◽  
pp. 205-213 ◽  
Author(s):  
Vhahangwele Masindi ◽  
Mugera W. Gitari
Keyword(s):  
Aqueous Solution ◽  
Adsorption Isotherms ◽  
Boron Concentration ◽  
Chemical Species ◽  
Aqueous System ◽  
World Health ◽  
Aqueous Systems ◽  
Ph Optimum ◽  
Boron Ions ◽  
Health Organization

The present study aimed to evaluate the efficiency of using cryptocrystalline magnesite to remove boron ions from aqueous systems. Batch experimental protocols were used to evaluate the adsorption capacity of magnesite for boron. Parameters optimized included: time, dosage, chemical species concentration and pH. Optimum conditions were observed to be 30 min of agitation, 1 g dosage of magnesite per 100 mL of aqueous solution and 20 mg/L initial boron concentration. Removal of boron from aqueous solution was observed to be independent of initial pH of the aqueous solution. The adsorption of boron onto magnesite was observed to fit better to pseudo-second-order kinetics than pseudo-first-order kinetics hence proving chemisorption. The intra-particle diffusion model revealed that the adsorption of boron from aqueous system occurs through multiple reaction phenomena. Adsorption isotherms proved that the removal of boron by magnesite fitted well to both Langmuir and Freundlich adsorption isotherms hence proving that both mono- and multi-site adsorption processes are taking place. Under optimized conditions, magnesite was able to attenuate the boron concentration to <0.01 mg/L which is below levels stipulated in World Health Organization guidelines. It was concluded that this comparative study will be helpful for further application of magnesite in remediation of boron-contaminated aqueous systems.

Mechanisms of Boron Removal with Electrocoagulation

2006 ◽  
Vol 3 (5) ◽  
pp. 350 ◽  
Author(s):  
Jia-Qian Jiang ◽  
Y. Xu ◽  
K. Quill ◽  
J. Simon ◽  
K. Shettle
Keyword(s):  
Drinking Water ◽  
World Health Organization ◽  
Solubility Product ◽  
Boron Concentration ◽  
Animal Health ◽  
World Health ◽  
Boron Removal ◽  
The World ◽  
Set Up ◽  
Health Organization

Environmental Context. Various environmental regulation organizations have set up standards or guidelines to regulate the boron concentration in drinking water, as a result of concern for human and animal health. In 2004, the World Health Organization Guidelines for Drinking Water Quality recommended boron values of no more than 0.5 mg L–1 in drinking water. Preliminary studies on boron removal with electrocoagulation have been carried out. However, in order to enhance boron removal using this method, and to meet the stringent guidelines set in place by the World Health Organization, there is a need to obtain a better understanding of how boron is removed from water by electrocoagulation. Abstract. This study aims to explore the mechanisms of boron removal by electrocoagulation (EC). The results demonstrate that adsorption and precipitation of boron by Al flocs are dominant mechanisms in boron removal using EC. The Al flocs that result from the EC process are found to be mainly composed of polymeric Al13 polymers (43%) and to have a long-lasting positive charge. These characteristics of the flocs contribute to the high levels of boron removal observed using EC. The maximum boron adsorption of the Al flocs is 200 mg g–1 and the solubility product constant (Ksp), which represents the boron precipitate Al(OH)2BO2·nH2O, is 2.6 × 10−40 (at 20°C).

scholarly journals Selective and Sensitive Detection of Cyanide Based on the Displacement Strategy Using a Water-Soluble Fluorescent Probe

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Ming La ◽  
Yuanqiang Hao ◽  
Zhaoyang Wang ◽  
Guo-Cheng Han ◽  
Lingbo Qu
Keyword(s):  
Aqueous Solution ◽  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Water Soluble ◽  
World Health ◽  
Selective Detection ◽  
Highly Sensitive ◽  
Health Organization

A water-soluble fluorescent probe (C-GGH) was used for the highly sensitive and selective detection of cyanide (CN−) in aqueous media based on the displacement strategy. Due to the presence of the recognition unit GGH (Gly-Gly-His), the probeC-GGH can coordinate with Cu2+and consequently display ON-OFF type fluorescence response. Furthermore, thein situformed nonfluorescentC-GGH-Cu2+complex can act as an effective OFF-ON type fluorescent probe for sensing CN−anion. Due to the strong binding affinity of CN−to Cu2+, CN−can extract Cu2+fromC-GGH-Cu2+complex, leading to the release ofC-GGH and the recovery of fluorescent emission of the system. The probeC-GGH-Cu2+allowed detection of CN−in aqueous solution with a LOD (limit of detection) of 0.017 μmol/L which is much lower than the maximum contaminant level (1.9 μmol/L) for CN−in drinking water set by the WHO (World Health Organization). The probe also displayed excellent specificity for CN−towards other anions, including F−, Cl−, Br−, I−, SCN−,PO43-,N3-,NO3-, AcO−,SO42-, andCO32-.

Boron Removal by Means of Precipitation Process with Magnesium Hydroxide

2013 ◽  
Vol 699 ◽  
pp. 262-267
Author(s):  
Nalan Erdöl Aydın
Keyword(s):  
Magnesium Hydroxide ◽  
Industrial Development ◽  
Boron Concentration ◽  
World Health ◽  
Precipitation Process ◽  
Boron Compounds ◽  
Living Organisms ◽  
Health Organization ◽  
Harmful Effects ◽  
Borate Salts

The presence of boron compounds in waters increases in a continuous and parellel way to industrial development. Therefore, their harmful effects an living organisms also increases, especially on plants, since this element manifests an important micronutrient-toxic boron duality. Boron is widely distributed in the environment, mainly in the form of boric asid or borate salts. Generally speaking, this element is an important micronutrient for living organisms, but the range between deficiency and excess is narrow. For this reason, the World Health Organization (WHO) recommendsin ist Guidelines for Drinking-Water Quality, a maximum boron concentration of 0.3 mgL-1. The same norms are recommended when seawater is used as a source of water. The aim of this study to investigate the influence of different operation variables within the precipitation process of boron with magnesium hydroxide when boron stock solution is being treated. Operation variables are precipitant amount, stirring speed, contact duration, pH, temperature.

Obstacles to Claiming Permanence and Injury-Relatedness for “Posttraumatic” Headache

2009 ◽  
Vol 14 (3) ◽  
pp. 3-6
Author(s):  
Robert J. Barth
Keyword(s):  
Complete Recovery ◽  
World Health ◽  
Related Factors ◽  
Posttraumatic Headache ◽  
Sixth Edition ◽  
Causative Relationship ◽  
Short Period ◽  
The One ◽  
Health Organization ◽  
Subjective Reports

Abstract “Posttraumatic” headaches claims are controversial because they are subjective reports often provided in the complex of litigation, and the underlying pathogenesis is not defined. This article reviews principles and scientific considerations in the AMAGuides to the Evaluation of Permanent Impairment (AMA Guides) that should be noted by evaluators who examine such cases. Some examples in the AMA Guides, Sixth Edition, may seem to imply that mild head trauma can cause permanent impairment due to headache. The author examines scientific findings that present obstacles to claiming that concussion or mild traumatic brain injury is a cause of permanent headache. The World Health Organization, for example, found a favorable prognosis for posttraumatic headache, and complete recovery over a short period of time was the norm. Other studies have highlighted the lack of a dose-response correlation between trauma and prolonged headache complaints, both in terms of the frequency and the severity of trauma. On the one hand, scientific studies have failed to support the hypothesis of a causative relationship between trauma and permanent or prolonged headaches; on the other hand, non–trauma-related factors are strongly associated with complaints of prolonged headache.

Sixth Edition: the New Standard

2008 ◽  
Vol 13 (1) ◽  
pp. 1-12
Author(s):  
Christopher R. Brigham ◽  
Robert D. Rondinelli ◽  
Elizabeth Genovese ◽  
Craig Uejo ◽  
Marjorie Eskay-Auerbach
Keyword(s):  
Review Process ◽  
Peer Review Process ◽  
World Health ◽  
International Classification Of Functioning ◽  
Revision Process ◽  
Sixth Edition ◽  
Impairment Ratings ◽  
Health Organization ◽  
Impairment Severity

Abstract The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, was published in December 2007 and is the result of efforts to enhance the relevance of impairment ratings, improve internal consistency, promote precision, and simplify the rating process. The revision process was designed to address shortcomings and issues in previous editions and featured an open, well-defined, and tiered peer review process. The principles underlying the AMA Guides have not changed, but the sixth edition uses a modified conceptual framework based on the International Classification of Functioning, Disability, and Health (ICF), a comprehensive model of disablement developed by the World Health Organization. The ICF classifies domains that describe body functions and structures, activities, and participation; because an individual's functioning and disability occur in a context, the ICF includes a list of environmental factors to consider. The ICF classification uses five impairment classes that, in the sixth edition, were developed into diagnosis-based grids for each organ system. The grids use commonly accepted consensus-based criteria to classify most diagnoses into five classes of impairment severity (normal to very severe). A figure presents the structure of a typical diagnosis-based grid, which includes ranges of impairment ratings and greater clarity about choosing a discreet numerical value that reflects the impairment.

The Historical Development of Burden of Treatment Compliance

2014 ◽  
Vol 19 (5) ◽  
pp. 13-15
Author(s):  
Stephen L. Demeter
Keyword(s):  
Internal Medicine ◽  
Treatment Compliance ◽  
World Health ◽  
International Classification Of Functioning ◽  
Sixth Edition ◽  
Burden Of Treatment ◽  
Specific Goal ◽  
Surrogate Measure ◽  
Health Organization

Abstract A long-standing criticism of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) has been the inequity between the internal medicine ratings and the orthopedic ratings; in the comparison, internal medicine ratings appear inflated. A specific goal of the AMA Guides, Sixth Edition, was to diminish, where possible, those disparities. This led to the use of the International Classification of Functioning, Disability, and Health from the World Health Organization in the AMA Guides, Sixth Edition, including the addition of the burden of treatment compliance (BOTC). The BOTC originally was intended to allow rating internal medicine conditions using the types and numbers of medications as a surrogate measure of the severity of a condition when other, more traditional methods, did not exist or were insufficient. Internal medicine relies on step-wise escalation of treatment, and BOTC usefully provides an estimate of impairment based on the need to be compliant with treatment. Simplistically, the need to take more medications may indicate a greater impairment burden. BOTC is introduced in the first chapter of the AMA Guides, Sixth Edition, which clarifies that “BOTC refers to the impairment that results from adhering to a complex regimen of medications, testing, and/or procedures to achieve an objective, measurable, clinical improvement that would not occur, or potentially could be reversed, in the absence of compliance.

Alexithyme Patientenmerkmale und Lebensqualität – Eine Querschnittsstudie an 79 ambulanten Patienten mit Angststörungen

2013 ◽  
Vol 61 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Katrin Leenen ◽  
Michael Rufer ◽  
Hanspeter Moergeli ◽  
Hans-Jörgen Grabe ◽  
Josef Jenewein ◽  
...  
Keyword(s):  
Quality Of Life ◽  
World Health ◽  
Life Questionnaire ◽  
World Health Organization Quality ◽  
Fand Sich ◽  
Quality Of Life Questionnaire ◽  
Organization Quality ◽  
Health Organization ◽  
Tas 20

Aus Untersuchungen in der Normalbevölkerung ist bekannt, dass Menschen mit erhöhten Alexithymiewerten eine verminderte Lebensqualität (LQ) aufweisen. Für Patienten mit psychischen Störungen wurde dieser Zusammenhang jedoch kaum untersucht. Ziel dieser Studie war es, den möglichen Zusammenhang zwischen alexithymen Patientenmerkmalen und der LQ bei Patienten mit Angststörungen zu überprüfen. Bei 79 ambulanten Patienten mit Angststörungen wurden alexithyme Charakteristika mit der Toronto Alexithymia Scale (TAS-20), die LQ mit der Kurzversion des World Health Organization Quality of Life Questionnaire 100 (WHOQOL-BREF) erfasst. Darüber hinaus fand eine Erhebung der psychischen Symptombelastung (SCL-90-R) und depressiven Symptomatik (MADRS) statt. Mittels hierarchischer Regressionsanalysen wurde der Zusammenhang zwischen der alexithymen Charakteristika und den unterschiedlichen LQ-Domänen berechnet. Die Patienten zeigten eine im Vergleich zur Normalbevölkerung deutlich verminderte LQ. Als Hauptergebnis fand sich, auch nach Kontrolle von Depression, Ängstlichkeit und Geschlecht, ein signifikanter Zusammenhang zwischen den beiden TAS-20 Subskalen Schwierigkeiten, Gefühle zu identifizieren und zu beschreiben und vor allem der psychischen LQ. Unsere Ergebnisse sprechen dafür, bei der Diagnostik und Therapieplanung von Patienten mit Angststörungen alexithyme Merkmale einzubeziehen. Im Falle von ausgeprägten alexithymen Merkmalen sollten psychotherapeutische Interventionen zur Verbesserung der Schwierigkeiten Gefühle wahrzunehmen und zu kommunizieren in Betracht gezogen werden.

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