Search query: Water treatment by nano technology

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abstract: In recent years, semiconductor photocatalytic process has shown a great potential as a low cost, environmental friendly and sustainable treatment technology to align with the "zero" waste scheme in the water/wastewater industry. The ability of this advanced oxidation technology has been widely demonstrated to remove persistent organic compounds and microorganisms in water. At present, the main technical barriers that impede its commercialisation remained on the post recovery of the catalyst particles after water treatment. This paper reviews the recent R&D progresses of engineered photocatalysts, photoreactor systems, and the process optimizations and modellings of the photooxidation processes for water treatment. A number of potential and commercial photocatalytic reactor configurations are discussed, in particular the photocatalytic membrane reactors. The effects of key photoreactor operation parameters and water quality on the photo process performances in terms of the mineralization and disinfection are assessed. For the first time, we describe how to utilize a multi variables optimization approach to determine the optimum operation parameters so as to enhance process performance and photooxidation efficiency. Both photomineralization and photo disinfection kinetics and their modellings associated with the photocatalytic water treatment process are detailed. A brief discussion on the life cycle assessment for retrofitting the photocatalytic technology as an alternative waste treatment process is presented. This paper will deliver a scientific and technical overview and useful information to scientists and engineers who work in this field.
author_names: Meng Nan Chong

Bo Jin

Christopher W K Chow

Christopher P Saint
title: Recent developments in photocatalytic water treatment technology: a review.
venue: Water research
year: 2010

abstract: Among various water purification and recycling technologies, adsorption is a fast, inexpensive and universal method. The development of low cost adsorbents has led to the rapid growth of research interests in this field. The present protocol describes salient features of adsorption and details experimental methodologies for the development and characterization of low cost adsorbents, water treatment and recycling using adsorption technology including batch processes and column operations. The protocol describes the development of inexpensive adsorbents from waste materials, which takes only 1 2 days, and an adsorption process taking 15 120 min for the removal of pollutants. The applications of batch and column processes are discussed, along with suggestions to make this technology more popular and applicable.
author_names: Imran Ali

V K Gupta
title: Advances in water treatment by adsorption technology
venue: Nature Protocols
year: 2007

abstract: Reverse osmosis membrane technology has developed over the past 40 years to a 44% share in world desalting production capacity, and an 80% share in the total number of desalination plants installed worldwide. The use of membrane desalination has increased as materials have improved and costs have decreased. Today, reverse osmosis membranes are the leading technology for new desalination installations, and they are applied to a variety of salt water resources using tailored pretreatment and membrane system design. Two distinct branches of reverse osmosis desalination have emerged: seawater reverse osmosis and brackish water reverse osmosis. Differences between the two water sources, including foulants, salinity, waste brine (concentrate) disposal options, and plant location, have created significant differences in process development, implementation, and key technical problems. Pretreatment options are similar for both types of reverse osmosis and depend on the specific components of the water source. Both brackish water and seawater reverse osmosis (RO) will continue to be used worldwide; new technology in energy recovery and renewable energy, as well as innovative plant design, will allow greater use of desalination for inland and rural communities, while providing more affordable water for large coastal cities. A wide variety of research and general information on RO desalination is available; however, a direct comparison of seawater and brackish water RO systems is necessary to highlight similarities and differences in process development. This article brings to light key parameters of an RO process and process modifications due to feed water characteristics.
author_names: Lauren F Greenlee

Desmond F Lawler

Benny D Freeman

Benoit Marrot

Philippe Moulin
title: Reverse osmosis desalination: water sources, technology, and today's challenges.
venue: Water research
year: 2009

abstract: One of the most pervasive problems afflicting people throughout the world is inadequate access to clean water and sanitation. Problems with water are expected to grow worse in the coming decades, with water scarcity occurring globally, even in regions currently considered water rich. Addressing these problems calls out for a tremendous amount of research to be conducted to identify robust new methods of purifying water at lower cost and with less energy, while at the same time minimizing the use of chemicals and impact on the environment. Here we highlight some of the science and technology being developed to improve the disinfection and decontamination of water, as well as efforts to increase water supplies through the safe re use of wastewater and efficient desalination of sea and brackish water.
author_names: Mark A Shannon

Paul W Bohn

Menachem Elimelech

John G Georgiadis

Benito J Marinas

Anne M Mayes
title: Science and technology for water purification in the coming decades
venue: Nature
year: 2008

abstract: The global population is increasing and because of this, the world may experience great fresh water scarcity. Our water resources are limited and, hence, water treatment and recycling methods are the only alternatives for getting fresh water in the coming decades. Therefore, there is a great need for the development of a suitable, inexpensive and rapid wastewater treatment techniques and reuse or conservation methods in the present century. The different types of water treatment and recycling techniques have been discussed in terms of their basic principles, applications, costs, maintenance and suitability. Additionally, a systematic approach to water treatment and recycling involving their understanding, evaluation and selection parameters has been presented. A brief guideline for the selection of the appropriate technologies for specific applications has been evaluated. This review adds to the global discussions on water scarcity solutions.
author_names: Vinod K Gupta

Imran Ali

Tawfik A Saleh

Arunima Nayak

Shilpi Agarwal
title: Chemical treatment technologies for waste water recycling an overview
year: 2012

abstract: Morpholino phosphorodiamidate antisense oligonucleotides (MOs) and short interfering RNAs (siRNAs) are commonly used platforms to study gene function by sequence specific knockdown. Both technologies, however, can elicit undesirable off target effects. We have used several model genes to study these effects in detail in the zebrafish, Danio rerio. Using the zebrafish embryo as a template, correct and mistargeting effects are readily discernible through direct comparison of MO injected animals with well studied mutants. We show here indistinguishable off targeting effects for both maternal and zygotic mRNAs and for both translational and splice site targeting MOs. The major off targeting effect is mediated through p53 activation, as detected through the transferase mediated dUTP nick end labeling assay, acridine orange, and p21 transcriptional activation assays. Concurrent knockdown of p53 specifically ameliorates the cell death induced by MO off targeting. Importantly, reversal of p53 dependent cell death by p53 knockdown does not affect specific loss of gene function, such as the cell death caused by loss of function of chordin. Interestingly, quantitative reverse transcriptase PCR, microarrays and whole mount in situ hybridization assays show that MO off targeting effects are accompanied by diagnostic transcription of an N terminal truncated p53 isoform that uses a recently recognized internal p53 promoter. We show here that MO off targeting results in induction of a p53 dependent cell death pathway. p53 activation has also recently been shown to be an unspecified off target effect of siRNAs. Both commonly used knockdown technologies can thus induce secondary but sequence specific p53 activation. p53 inhibition could potentially be applicable to other systems to suppress off target effects caused by other knockdown technologies.
author_names: Mara E Robu

Jon D Larson

Aidas Nasevicius

Soraya Beiraghi

Charles Brenner

Steven Arthur Farber

Stephen C Ekker
title: p53 Activation by Knockdown Technologies
venue: PLoS genetics
year: 2007

abstract: 1. Introduction 2. Theoretical foundations 3. Propagation and focusing of optical fields 4. Spatial resolution and position accuracy 5. Nanoscale optical microscopy 6. Near field optical probes 7. Probe sample distance control 8. Light emission and optical interaction in nanoscale environments 9. Quantum emitters 10. Dipole emission near planar interfaces 11. Photonic crystals and resonators 12. Surface plasmons 13. Forces in confined fields 14. Fluctuation induced phenomena 15. Theoretical methods in nano optics Appendices Index.
author_names: Lukas Novotny

Bert Hecht
title: Principles of nano optics
year: 2006

abstract: The elimination of selected pharmaceuticals (bezafibrate, clofibric acid, carbamazepine, diclofenac) during drinking water treatment processes was investigated at lab and pilot scale and in real waterworks. No significant removal of pharmaceuticals was observed in batch experiments with sand under natural aerobic and anoxic conditions, thus indicating low sorption properties and high persistence with nonadapted microorganisms. These results were underscored by the presence of carbamazepine in bank filtrated water with anaerobic conditions in a waterworks area. Flocculation using iron(III) chloride in lab scale experiments (Jar test) and investigations in waterworks exhibited no significant elimination of the selected target pharmaceuticals. However, ozonation was in some cases very effective in eliminating these polar compounds. In lab scale experiments, 0.5 mg/L ozone was shown to reduce the concentrations of diclofenac and carbamazepine by more than 90% while bezafibrate was eliminated by 50% with a 1.5 mg/L ozone dose. Clofibric acid was stable even at 3 mg/L ozone. Under waterworks conditions, similar removal efficiencies were observed. In addition to ozonation, filtration with granular activated carbon (GAC) was very effective in removing pharmaceuticals. Except for clofibric acid, GAC in pilot scale experiments and waterworks provided a major elimination of the pharmaceuticals under investigation.
author_names: Thomas A Ternes

Martin Meisenheimer

Derek McDowell

Frank Sacher

H J Brauch

Brigitte Haist-Gulde

Gudrun Preuss

U Wilme

Ninette Zulei-Seibert
title: Removal of pharmaceuticals during drinking water treatment.
venue: Environmental science technology
year: 2002

abstract: Abstract Although micro and nano bubble technology has been attracting attention in many fields, the state of water after the introduction of those bubbles is still not clear. In this study, the existence and stabilization of nano bubbles after the generation of bubbles were investigated. The presence of nano sized particles was detected through dynamic light scattering for days, when pure oxygen was used to generate the bubbles, and for less than 1 h, in the case of air bubbles. NMR spin lattice relaxation time increased with the introduction of micro and nano bubbles in manganese ions solution, indicating the presence of a gas liquid interface which adsorbed the manganese ions. Furthermore, the zeta potential measured in the water after the introduction of oxygen micro and nano bubbles was in the range from 45 mV to 34 mV and from 20 mV to 17 mV in water bubbled with air, indicating the presence of stable electrically charged particles. This study suggested a strong possibility of the existence of nano bubbles in water for a long time. The stability of nano bubbles is supported by the electrically charged liquid gas interface, which creates repulsion forces that prevent the bubble coalescence, and by the high dissolved gas concentration in the water, which keeps a small concentration gradient between the interface and the bulk liquid.
author_names: Fernanda Yumi Ushikubo

T Furukawa

Ryo Nakagawa

Masato Enari

Yoshio Makino

Yoshinori Kawagoe

Takeo Shiina

Seiichi Oshita
title: Evidence of the existence and the stability of nano bubbles in water
year: 2010

abstract: Spray drying technology is widely known and used to transform liquids (solutions, emulsions, suspension, slurries, pastes or even melts) into solid powders. Its main applications are found in the food, chemical and materials industries to enhance ingredient conservation, particle properties, powder handling and storage etc. However, spray drying can also be used for specific applications in the formulation of pharmaceuticals for drug delivery (e.g. particles for pulmonary delivery) Buchi is a reference in the development of spray drying technology, notably for laboratory scale devices. This study presents the Nano Spray Dryer B 90, a revolutionary new sprayer developed by Buchi, use of which can lower the size of the produced dried particles by an order of magnitude attaining submicron sizes. In this paper, results are presented with a panel of five representative polymeric wall materials (arabic gum, whey protein, polyvinyl alcohol, modified starch, and maltodextrin) and the potentials to encapsulate nano emulsions, or to formulate nano crystals (e.g. from furosemide) are also shown.
author_names: Xiang Li

Nicolas Anton

Cordin Arpagaus

Fabrice Belleteix

Thierry F Vandamme
title: Nanoparticles by spray drying using innovative new technology: the Buchi nano spray dryer B 90.
venue: Journal of controlled release official journal of the Controlled Release Society
year: 2010