Fabrication of smart glass electrochromic device using rf magnetron sputtering

Electrochromic device is an important functional device to control the amount of light through a glass. It usually used in sunlight control window glazing for buildings and automobile. The important feature of electrochromic glass is the ability to response toward the apply voltage in shortest time, and endurance to maintain in color shape after apply voltage. In this thesis, the oxygen gas percentage is optimized during the fabrication of tungsten trioxide (WO3) as an electrochromic glass for window glazing application by using RF magnetron sputtering. The oxygen flow rate for the deposition is varied from 10sccm -22sccm which is 25%, 27%, 30%, and 35% of oxygen flow. The structures of WO3 were investigated using X-Ray diffraction, Field effect scanning electron microscopy (Fe-Sem) and Atomic force microscopy (AFM). The electrochromic properties were characterized by a cyclic voltammogram and UV-Vis absorption spectra. The results show that nanocrystalline film with particle size of 51.54nm was deposited at 27% oxygen flow rate has the largest charge capacity and coloration efficiency among the others. The time respond taken for complete coloration at 4V is 2second. This result is a starting point for future work such as optimizing the film thickness or doping by other metals

Adsorption of phosphate from aqueous solution onto iron-coated waste mussel shell: physicochemical characteristics, kinetic, and isotherm studies

High amounts of phosphate (PO43–) discharged in receiving water can lead to eutrophication, which endangers life below water and human health. This study elucidates the removal of PO43– from synthetic solution by iron-coated waste mussel shell (ICWMS). The PO4 3– adsorption by ICWMS was determined at different process parameters, such as initial PO43– concentration (7 mg L−1), solution volume (0.2 L), adsorbent dosage (4, 8, 12, 16, and 20 g), and contact time. The highest efficiency of PO43− removal can reach 96.9% with an adsorption capacity of 0.30 mg g−1 could be obtained after a contact time of 48 h for the use of 20 g of ICWMS. Batch experimental data can be well described by the pseudo-second-order kinetic model (R2 = 0.999) and Freundlich isotherm model (R2 = 0.996), suggesting that chemisorption and multilayer adsorption occurred. The efficiency of PO43– removal from aqueous solution by ICWMS was verified to contribute to applying a new low-cost adsorbent obtained from waste mussel shell in the field of wastewater treatment

Photoreduction of Pb(II) ions from aqueous solution by titania polyvinylalcohol–alginate beads

Knowing the photocatalytic reduction of heavy metal ions in waters is of interest and putting this to practical options for improving the environment performance. The purpose of this study was to assess effectiveness of the titania polyvinylalcohol–alginate beads (TPVAABs) as photocatalyst in the removal of Pb(II) ions from aqueous solution, compared to the maghemite polyvinylalcohol–alginate beads (MPVAABs). This study performed the tests of photoreduction of Pb(II) ions by both TPVAABs and TPVAABs in batch experiments. The results showed that the use of TPVAABs could be effective to remove Pb(II) ions from aqueous solution with 98% efficiency after 135 min of reaction time under sunlight irradiation, compared with 98.3% efficiency for the use of MPVAABs. The desorption of Pb(II) ions for the first cycle of adsorption/desorption appeared to be optimal for the TPVAABs recovery. The photocatalytic reduction of Pb(II) ions by TPVAABs can be used repeatedly more than seven cycles of adsorption/desorption. The present study reported photoreduction treatment system to remove Pb(II) ions from aqueous solution by TPVAABs, as well as by MPVAABs, represents a rapid and reliable method to strengthening physicochemical process of treating metal-contaminated wastewater in the future

Silver nanoparticles adsorption by the synthetic and natural adsorbent materials: an exclusive review

Silver nanoparticles (AgNPs) have been used in a wide range of industrial products. The release of AgNPs as antimicrobial agent into the river or lake can raise the ecological concern because they have been proven to be associated with toxicity of the aquatic animals. An exclusive review of AgNPs adsorbed by the various synthetic and natural adsorbent materials is important to understand the behaviour of AgNPs in the complex environmental conditions. The transformation of AgNPs into various forms in an aquatic environment depends on the physical, chemical, and biological characteristics of water. Many types of natural materials can be used to fabricate the adsorbents because pore structure, surface area, and active sites of functional groups of the adsorbent can be developed during the carbonisation and activation stages. The mass transfer factor and modified mass transfer factor models would be considered tools that can be used to describe the mechanism and kinetics of AgNPs adsorption onto the natural adsorbents influenced by the electrostatic and van der Waals forces. This exclusive review provides the valuable insights into future challenges of AgNPs adsorption to contribute to sustainable improvement in the management of aquatic ecosystems

Kinetics and mass transfer studies on the biosorption of organic matter from palm oil mill effluent by aerobic granules before and after the addition of Serratia marcescens SA30 in a sequencing batch reactor

Kinetic and mass transfer aspects of biosorption of oxidisable organic matter (OOM) from wastewater are important for better understanding of the mechanisms of granules initiation and development. The modified mass transfer factor models were used to predict the liquid–solid mass transfer rates of OOM biosorption from palm oil mill effluent (POME) attached to aerobic granular sludge (AGS) in a sequencing batch reactor (SBR). The variations of [kLa]g, [kLa]f and [kLa]d pursuant to time were verified to have a zigzag pattern due to the organic loading rate varies with a change in the quality of POME feeding the SBR. The influence of added Serratia marcescens SA30 on the rates of mass transfer would be very remarkable due to the effects of metabolites and biomass growth this can lead to a rapid utilisation of OOM accumulated into AGS. The maximum efficiencies of SBR reaching 48% for CODt removal at [kLa]g value of 3.054 h−1 and 68% for CODs removal at [kLa]g value of 21.012 h−1 were verified before the addition of S. marcescens SA30 and those reaching 68% for CODt removal at [kLa]g value of 1.229 × 1063 h−1 and 94% for CODs removal at [kLa]g value of 7.152 × 1064 h−1 were verified after the addition of S. marcescens SA30. The resistance of mass transfer could be dependent on external mass transfer, which controls the movement of organic molecules along the experimental period of POME fed the SBR without and with added S. marcescens SA30. The performance of SBR would increase with increase of [kLa]g value, and this provides new insight into dynamic response of the aerobic digestion to AGS development

Mass transfer kinetics of Cd(II) ions adsorption by titania polyvinylalcohol-alginate beads from aqueous solution

Kinetic assessment of the photoreduction of Cd(II) ions in aqueous solution is of interest and thus can most definitely help us make better measures of the scientific concepts to improving the environmental performance. This study showed that the use of titania polyvinylalcohol-alginate beads (TPVA-ABs) as photocatalyst could be effective to remove Cd(II) ions from aqueous solution. The efficiency of Cd(II) ions removal can be expected at 100% for an initial Cd(II) concentration of 50 mg L−1, compared with the efficiencies of 91.2 and 83.6% for the initial Cd(II) concentrations of 100 and 200 mg L−1, respectively, after 3-h reaction time under sunlight irradiation. The desorption capacities of Cd(II) ions in TPVA-ABs were verified for five consecutive cycles of adsorption/desorption to be less than 3% of the reduced Cd(II) ion removal efficiency. Photoreduction of Cd(II) ions by the TPVA-ABs can be used repeatedly at least for five cycles of adsorption/desorption and showed very little loss of its initial properties. The present study scrutinised mass transfer kinetics of Cd(II) ions adsorption by the TPVA-ABs promotes a rapid method to strengthening the adsorption process of treating Cd-contaminated wastewater in the future

Mass transfer kinetics of biosorption of nitrogenous matter from palm oil mill effluent by aerobic granules in sequencing batch reactor

Understanding of mass transfer kinetics is important for biosorption of nitrogen compounds from palm oil mill effluent (POME) to gain a mechanistic insight into future biological processes for the treatment of high organic loading wastewater. In this study, the rates of global and sequential mass transfer were determined using the modified mass transfer factor equations for the experiments to remove nitrogen by aerobic granular sludge accumulation in a sequencing batch reactor (SBR). The maximum efficiencies as high as 97% for the experiment run at [kLa]g value of 1421.8 h−1 and 96% for the experiment run at [kLa]g value of 9.6 × 1037 h−1 were verified before and after the addition of Serratia marcescens SA30, respectively. The resistance of mass transfer could be dependent on external mass transfer that controls the transport of nitrogen molecule along the experimental period of 256 days. The increase in [kLa]g value leading to increased performance of the SBR was verified to contribute to the future applications of the SBR because this phenomenon provides new insight into the dynamic response of biological processes to treat POME

A water balance approach for assessing the potential source of water in Dohuk Dam for agricultural, domestic and tourism purposes

Water balance approaches have been widely used to stimulate and forecast the average runoff and river discharge in small- and medium-sized basins. The analysis of water balance for Feesh Khabour River and Dohuk Dam catchment areas needs to be verified. This study used 24 alternative scenarios for assessing the robustness of adaptation decisions to water management practices. The discharge of Feesh Khabour River recorded at Zakho station, with a maximum flow rate of higher than 19.6 m cm d-1 and a minimum flow rate of 0.3 m cm d-1, helps ensure that interbasin water transfer remains one of the most attractive alternatives for increasing the amount of water available in the Dohuk Dam for agricultural, domestic and tourism uses

Formaldehyde removal mechanisms in a biotrickling filter reactor

Formaldehyde (FA) is one of toxic, mutagen, suspected carcinogen and teratogen pollutants presented in contaminated air and might be commonly released from a wide range of the industrial activities. Even though many studies have been made to remove FA from synthetic contaminated air stream (SCAS) using a biotrickling filter reactor (BTFR), the mechanisms of FA removal by a BTFR treatment process must to be verified. The aim of this study was to perform the laboratory-scale BTFR experiments to remove FA from the SCAS during a period of 21 days after passing an adaptation phase of 90 days. The mechanisms of FA removal from SCAS in biofilter must pass through two successive stages: (1) the first diffuses FA from gas phase to aqueous phase to form formic acid and methanol and (2) the second guarantees that the predominant microorganisms are able to metabolise the chemicals-derived FA from aqueous phase for growth and maintenance of life. The research findings may lead to better understanding of the BTFR design and operations to reduce air pollutants in order to maintain or improve air quality

Assessing the treatment of acetaminophen-contaminated brewery wastewater by an anaerobic packed-bed reactor

The treatment of high-strength organic brewery wastewater with added acetaminophen (AAP) by an anaerobic digester was investigated. An anaerobic packed-bed reactor (APBR) was operated as a continuous process with an organic loading rate of 1.5-g COD per litre per day and a hydraulic retention time of three days. The results of steady-state analysis showed that the greatest APBR performances for removing COD and TOC were as high as 98 and 93%, respectively, even though the anaerobic digestibility after adding the different AAP concentrations of 5, 10 and 15 mg L(-1) into brewery wastewater can affect the efficiency of organic matter removal. The average CH4 production decreased from 81 to 72% is counterbalanced by the increased CO2 production from 11 to 20% before and after the injection of AAP, respectively. The empirical kinetic models for substrate utilisation and CH4 production were used to predict that, under unfavourable conditions, the performance of the APBR treatment process is able to remove COD with an efficiency of only 6.8%