Materials For Water Purification Research Articles

Ultra-fine cellulose nanofibers: new nano-scale materials for water purification

The major challenges in membrane technology for water filtration are the development of new materials (e.g. high durability, low cost and low environmental concerns) and new structures (e.g. directed water channels) that can produce high permeation flux (thus low energy input) while maintaining a high selectivity or rejection rate. This highlight discusses the utilization of ultra-fine cellulose nanofibers (UCN, diameter 5–10 nm), made by TEMPO/NaBr/NaClO oxidation of natural cellulose (e.g. wood pulp), in different nanofibrous composite formats that can meet this challenge for microfiltration (MF) and ultrafiltration (UF) applications. The unique features of ultra-fine cellulose nanofibers include small diameter, high surface-to-volume ratio, easy surface functionality, good mechanical properties and good chemical resistance. The electrospun nanofibrous scaffolds with fine pore size defined by the fiber diameter could be used to remove waterborne bacteria at two to three times higher flux when compared to that of commercial MF membranes (e.g., Millipore GS9035). When UCN were used as a functionalized adsorbent infused in the asymmetric two-layered non-woven fibrous format, the membranes exhibited a high ability to remove bacteria (by size exclusion) and viruses (by adsorption) simultaneously. When UCN were used as the barrier layer in an asymmetric three-layered non-woven fibrous format containing fibers of different diameters (from 5 nm to 20 µm), the membranes exhibited a two- to ten-fold increase in permeation flux over commercial membranes for ultrafiltration of oil and water emulsions (e.g., for purification of bilge water in ships or industrially produced water).

Functional Dendritic Polymers for the Development of Hybrid Materials for Water Purification

AbstractDendritic polymers can, depending on their polarity and the interaction ability of their interior, encapsulate water contaminants. By appropriate functionalization of their external groups and following integration with ceramics, hybrid devices bearing nanosized sorbents are developed. In a first strategy, hydrophobic dendritic polymers were non‐covalently attached on the surface of ceramic filter modules, while in a second, dendritic polymers were covalently bound on these surfaces. In another method, dendritic polymers act as templates and induce the formation of silica/dendritic polymer nanospheres. In all cases, the property of dendritic polymers to encapsulate impurities remains intact, leading to effective filtration/purification systems.magnified image

Use of nanomaterials in water purification

The recent earthquake in Haiti has focused worldwide attention on the need for improved water purification materials and systems. Numerous individuals, religious charities, non-governmental organizations, and private companies have sent water purifications systems to Haiti in recent months in order to stem the spread of waterborne diseases. This recent tragedy has placed a spotlight on the ongoing problem of inadequate access to safe water in developing countries. The United Nations estimates that 1.1 billion people, or eighteen per cent of the world population, cannot obtain safe water at this time 1 . In developing countries, waterborne diseases such as cholera, dysentery, enteric fever, and hepatitis A are quite common 2 . Endemic diarrheal diseases place individuals, particularly children, at risk of arrested growth, malnutrition, and neurological conditions. The World Health Organization states that 1.6 million individuals, mostly young children, die from diarrheal diseases each year 1 .

Geochemical And Mineralogical Characteristics Of Lithomargic Clay Types From Awaso Bauxite Deposit, Ghana: Implications For Possible Industrial Utilization

Stable Food Crops Turning Into Commercial Crops: Case studies of Teff, Wheat and Rice in Ethiopia Geochemical and mineralogical methods were employed in characterizing lithomargic clay types underlying Awaso lateritic bauxite deposit in southwestern Ghana in order to assess their suitability for possible industrial utilization. Representative samples analyzed from the deposit revealed kaolinite and gibbsite as the dominant minerals whilst accessory minerals found included goethite, rutile, biotite and muscovite with quartz conspicuously absent. It is possible to wash and separate most of the gibbsite component, which is prevalent in the > 90μm size fractions. On the basis of the results obtained from chemical and mineralogical analyses as well as diagnostic evaluative analyses, the lithomargic clay types could be exploited in the production of aluminium sulphate (alum) for water purification and alumino-silicate refractory material. The raw clay will however have to be beneficiated in order to optimize grade and recovery.

Water purification: from ancient civilization to the XXI Century

Ancient civilization valued the vital role of water in human life. As reflected in the literature, environmental awareness led to early water treatments and these are briefly described in this paper. Thus the period prior to 500 BC to 1000 AD saw the use of naturally occurring materials for water purification, the building of aqueducts, and the introduction of the distillation process. This was followed by a dormant period of five centuries in which hardly any progress was made in water purification methodology. From the 17th to the 19th century, progress was made on filtration processes and the introduction of the microscope. In addition chemical methods for water disinfection by the use of chlorine and ozone were reported. These methods and their combination progressed significantly through the 20th century. However the problems associated with chemical contamination of ground water, from which, drinking water is mainly generated remained practically ignored for about five decades. It was in the late seventies that this was brought to light. Since then technologies for groundwater purification started to emerge but a lot remains to be done in this area of research. The crucial role of suitable analytical tools for any technological development which aim to remove toxic pollutants from water is acknowledged. Thus the need of re-visiting old methodology making use of the advantages resulting from the availability of advanced analytical techniques and the possibility of enriching naturally occurring materials by the introduction of supramolecular receptors for water decontamination purposes are emphasized.

Fundamental Study on the Utilization of Demolished Concrete for Water Purification Material

Fundamental Study on the Utilization of Demolished Concrete for Water Purification Material

ビール粕を原料とする成形炭の水質浄化特性

The charcoal brick made from beer lees (CBBL) was investigated as the material for purification of lake water. The beer lees containing 67wt% water were first dried and then the dried beer lees were pressed at high temperature and pressure to make beer lees brick without any binder. The beer lees brick was carbonized in a low oxygen atmosphere to produce charcoal brick.The CBBL is useful for the carrier of microorganisms and it is possible to reduce soluble organisms and soluble nitrogen as same as charcoal. The CBBL contains phosphorus at the ratio of about 2wt%, which is soluble in water. The addition of 20wt% CaCO3 to the dried beer lees in the pressing process is beneficial to prevent solubilization of phosphorus in the CBBL. The CBBL does not have a weak point that it is abased in the purification column compared with the charcoal used in usual water purification.

Microporous filters with oxidizing power for iron and manganese removal from water

Abstract This report describes the development of a microporous filter carrying oxidizing power to convert the ionic species in water from soluble form, such as Fe+Z and Mn+2, to insoluble form, thus allowing for their continuous removal in one step. The filters were constructed with a celluloslc fiber network for immobilizing adsorbent particles carrying oxidizing power. The porosity of the filters was controlled by selecting the proper size of the binding fibers and the adsorbent. A number of substances were incorporated into the filter matrix and tested for their ability to remove soluble iron from water. Magnesium peroxide was found to be the most effective and was capable of removing significant quantities of iron from water at high flow rates. Removal is believed to take place by a combination of ferric ion adsorption, oxidation to insoluble ferrous hydroxide and filtration. Construction of filter cartridges demonstrated the effectiveness of the material for home water purification.

Possibilities of the use of local filtering materials for mine water purification

Possibilities of the use of local filtering materials for mine water purification