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Sichuan Basin (SCB) is a typical basin in southwest China and a traditional smog-prone area. Control of air pollution in this area is particularly critical in achieving China’s carbon emission peak and carbon neutral goals. It is characterized by high population density, heavy transportation, rapid industrialization, complex topography, and meteorological conditions. However, the air pollution studies of SCB remain the sparse and in-depth studies are still warranted. None of the previous research has synthetically reviewed the status of air pollution in this region. This paper comprehensively overviewed the air pollution of SCB from five aspects: air pollution characteristics, sources of air pollutants, driving factors of air pollution, air pollution episodes and health risks. A comparison on the air pollution of typical megacities in the basin was also discussed. The findings and shortcomings of the existing studies were also summarized. Recommendations for future research directions were also proposed.

A versatile synthetic approach for development of highly fluorescent nitrogen-doped carbon dots (N-CDs) from carboxymethylcellulose in the presence of linear polyethyleneimine (LPEI) has been developed. According to single factor method, central composite design incorporated with response surface methodology matrix was applied to find and model optimal conditions for the temperature (220–260 °C), duration (1–3 h) and LPEI weight (0.5–1.5%). The statistical results show that duration was the most significant parameter for efficient carbonization conversion rate in comparison with temperature and LPEI weight. The reduced cubic model (R2 = 0.9993) shows a good correlation between the experimental data and predicted values. The optimal variables were temperature of 260 °C, duration of 2 h and LPEI weight of 1%. Under these conditions, quantum yield of up to 44% was obtained. The numerically optimized N-CDs have an average size of 3.4 nm with graphitic nature owing to the abundant amino species incorporated into the carbon core framework. The blue-green N-CDs possess emission dependent upon the solvent polarity, wide pH stability with enhanced emission in an acidic environment. Impressively, the N-CDs show long-shelf-life for up to 1 year with no noticeable precipitation. The N-CDs were able to recognize a high concentration of Fe3+ ions with a detection limit of 0.14 μM in acidic solution owing to the special coordination for Fe3+ to be captured by electron-donating oxygen/ amino groups around N-CDs. Moreover, the N-CDs can also be used as a new kind of fluorescent ink for imaging applications.

Electrolyzed water (EW) shows great potential as a green and economical sanitation solution for the food industry. However, only limited studies have investigated the optimum electrolysis parameters and the bactericidal effect of acidic electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW). Here, the Box&ndash, Behnken experimental design was used to identify the optimum parameters. The tests were conducted with different types of electrodes, electrical voltages, electrolysis times, and NaCl concentrations. There were no obvious differences observed in the physico-chemical properties of EW when different electrodes were used. However, stainless steel was chosen as it meets most of the selection criteria. The best-optimized conditions for AcEW were at 11.39 V, 0.65 wt.% NaCl, and 7.23 min, while the best-optimized conditions for AlEW were at 10.32 V, 0.6 wt.% NaCl, and 7.49 min. The performance of the optimum EW (AcEW and AlEW) compared with commercial cleaning detergents for the food industry was then evaluated. The bactericidal activity of AcEW and AlEW was examined against Escherichia coli ATCC 10536 at different temperatures (30 &deg, C and 50 &deg, C) for 30 s. The results show that both AcEW and AlEW have the ability to reduce the Escherichia coli to non-detectable levels (less than 2 log CFU/mL).

Temitope, Dele-Afolabi/0000-0003-0187-9208; Sobri, Shafreeza/0000-0002-5675-2186 WOS: 000440527300010 In the present study, an analysis on the combined effect of nickel (Ni) reinforcement and pore former type in characterizing the corrosion behavior of composite porous alumina ceramics was performed. In order to showcase the potential of the new porous ceramics, pore-forming agents (PFAs) from rice husk (RH) and sugarcane bagasse (SCB) were used in shaping the plain and composite porous alumina samples having sample formulation of Al2O3-xNi-PFA; x = 0, 2, 4, 6 and 8 wt%. Results showed that the emergence of a highly stable Ni3Al2SiO8 spinelloid phase in the RH-graded composites enhanced their chemical stability in the corrosive mediums (10 wt% NaOH and 20 wt% H2SO4) relative to the plain and the corresponding SCB-graded counterparts. An artificial neural network (ANN) model has been developed for predicting the corrosion behavior of the plain and composite porous alumina ceramics based on the experimental data. The developed ANN model satisfactorily predicted the percent mass losses of the porous ceramics in strong alkali and strong acid solutions with coefficient of determination (R-2) of approximately 0.99. Research Management Center of Universiti Putra Malaysia [GP-IPS/2016/9486500]; Department of Metallurgy and Materials Engineering, Kirikkale University, Turkey [2016/44] The authors are thankful to the Research Management Center of Universiti Putra Malaysia for providing financial support (GP-IPS/2016/9486500) to carry out this research study. The authors also acknowledge the Department of Metallurgy and Materials Engineering, Kirikkale University, Turkey for the ongoing partnership, financial support (project number of 2016/44) and fruitful feedback.

Sobri, Shafreeza/0000-0002-5675-2186; Temitope, Dele-Afolabi/0000-0003-0187-9208 WOS: 000432768200015 The mechanical performance and chemical stability of porous alumina materials operating under harsh service conditions are of utmost importance in understanding their operational behavior if they are to stand the test of time. In the present study, the joint effect of nickel (Ni) reinforcement and rice husk (RH) pore-forming agent (PFA) on the tensile strength and the corrosion resistance properties of composite porous alumina ceramics was studied. To exploit the potential of this new porous alumina system, plain and Ni-reinforced porous alumina samples (Al2O3-xNi-RH; x = 2, 4, 6 and 8 wt%) were developed through the powder metallurgy technique. Comprehensive investigation on the tensile strength properties of the developed porous alumina ceramics showed that relative to the plain sample (tensile strength and elastic modulus; 6.1 MPa and 1201 MPa), the presence of highly stable Ni3Al2SiO8 spinelloid promoted the tensile strength enhancement (12.6-6.4 MPa) and the elastic modulus decline (897-627 MPa) of the composite samples. Similarly, corrosion resistance test was performed on the composite porous alumina samples in both 10wt% NaOH and 20wt% H2SO4 hot aqueous solutions. Overall, the composite samples demonstrated superior chemical stability in NaOH solution as compared with the plain sample. On the other hand, the composites were more prone to attack in H2SO4 solution, except for the Al2O3-2Ni-10RH composite sample which maintained its superiority over the plain counterpart. Research Management Center of Universiti Putra Malaysia [GP-IPS/2016/9486500] The authors are thankful to the Research Management Center of Universiti Putra Malaysia for providing financial support (GP-IPS/2016/9486500) to carry out this research study. The authors also acknowledge the Department of Metallurgy and Materials Engineering, Kirikkale University, Turkey for the ongoing partnership, endless support and fruitful feedback.

Temitope, Dele-Afolabi/0000-0003-0187-9208; Sobri, Shafreeza/0000-0002-5675-2186; Mazlan, Norkhairunnisa/0000-0003-0144-8360 WOS: 000427511200038 Porous alumina systems are suitable for application in wide-ranging industrial processes that require extreme service conditions such as high temperatures and corrosive mediums due to their remarkable thermal and chemical stability. Given the inherent brittleness of ceramics and their high sensitivity to thermo-mechanical loading, large-scale production of porous alumina components is constrained. In this study, the reinforcement of porous alumina ceramics with nickel (Ni) particles has been reported. Plain and Ni-reinforced porous alumina ceramics were developed through the powder metallurgy method with agro-waste materials from rice husk (RH) and sugarcane bagasse (SCB) as the pore-forming agents (PFAs). Experimental results showed that the formation of a stable Ni3Al2SiO8 spinelloid phase in the RH-graded composites actuated the emergence of a relatively refined microstructure while on the other hand, microstructural defects such as dislocated grains and localized voids were observed for the SCB-graded counterparts due to the presence of poorly crystallized NiAl2O4 spinel phase. Generally from the mechanical strength characterization, an inverse relationship was established between the mechanical properties and Ni reinforcement which agrees well with the Griffith's model. Moreover, the strengthening effect of the Ni3Al2SiO8 spinelloid phase was well marked in the RH-graded composites as maximum hardness, tensile and compressive strengths of 167.3HV, 12.6 MPa and 55.3 MPa respectively were achieved for the composite reinforced with 2 wt% Ni. (c) 2018 Elsevier B.V. All rights reserved. Research Management Center of Universiti Putra Malaysia [GP-IPS/2016/9486500]; Department of Metallurgy and Materials Engineering, Kirikkale University, Turkey [2016/44] The authors are thankful to the Research Management Center of Universiti Putra Malaysia for providing financial support (GP-IPS/2016/9486500) to carry out this research study. The authors also acknowledge the Department of Metallurgy and Materials Engineering, Kirikkale University, Turkey for the ongoing partnership, financial support (project number of 2016/44) and fruitful feedback.

Sobri, Shafreeza/0000-0002-5675-2186; Temitope, Dele-Afolabi/0000-0003-0187-9208 WOS: 000434275500025 This study demonstrates a simple and economically viable approach to fabricate porous alumina ceramics shaped with low-priced natural organic pore-forming agents (PFAs) from rice husk (RH) and sugarcane bagasse (SCB) of various weight contents using the powder metallurgy method. Experimental findings revealed that the total porosity (44-67vol%) and average pore size (70-178m) maintained a linear relationship with rising PFA inclusion. Using the diametral compression test, the mechanical response of porous alumina samples was evaluated as a function of porosity and pore geometry. From the overall mechanical strength characterization, the susceptivity of strength on porosity became well marked as the agro-waste shaped porous ceramics exhibited hardness, tensile strength, and elastic modulus of 529.1-26HV, 20.4-1.5MPa and 1662-57MPa, respectively. Moreover, the fractography of the RH and SCB graded porous alumina samples was evaluated as a function of the respective microstructural features. With a plausible tradeoff between pore interconnectivity and mechanical strength, recommended areas of application include solid oxide fuel cells (SOFCs) design, filtration, and thermal insulation systems. Research Management Center of Universiti Putra Malaysia [GP-IPS/2016/9486500]; Kirikkale University, Turkey [2016/44] Research Management Center of Universiti Putra Malaysia, Grant/Award Number: GP-IPS/2016/9486500; Kirikkale University, Turkey, Grant/Award Number: 2016/44

Macroporous ceramics with tailored porosity offer a great deal of advantage in wide-ranging industrial applications including fluid filtration, thermal insulation and lately, waste water treatment. To a large extent, attempts by researchers in enhancing the development of ample homogenous porous ceramics through the exploitation of state of the art processing technologies have thus far been successful. However, these technologies are capital intensive hence making room for more exploration in finding affordable alternatives. With the growing recognition of low cost sacrificial fugitives processing route for developing porous ceramic materials, pore forming agents from natural organic matters have been one of the most sought after materials for imbuing pores within ceramic matrices. This review intends to document the progress made thus far in the development of porous ceramic systems with natural organic matter inclusion. The article covers critical evaluation and comprehensive comparison of the fabrication routes and the physical properties of porous ceramics processed with varying natural organic matters.

The corrosion inhibitive characteristics of the cashew nut (Anacardium occidentale) were studied as an eco-friendly green corrosion inhibitor at ambient temperature of 25 °C using weight loss analysis and adsorption isotherms. The effect of inhibitor concentration (4–12 g/l) at immersion time of 3–12 days was evaluated. The inhibitive ability of cashew nut shows a significant inhibition efficiency of 86% at 12 g/l concentration for 3-days and 72.9% at 12-days, which are undoubtedly as a result of the absorption of the inhibitor molecules on the metal surface which serve as a barrier against corrosion of carbon steel in acidic medium. The adsorption mechanism was found to fit Tempkin isotherms. The average optimum free energy of absorption was calculated to be −17.374 kJ mol–1 indicating that the process was exothermic and physisorption.

The current research mainly focuses on transforming low-quality waste into value-added nanomaterials and investigating various ways of utilising them. The hydrothermal preparation of highly fluorescent N-doped carbon dots (N&ndash, CDs) was obtained from the carboxymethylcellulose (CMC) of oil palm empty fruit bunches and linear-structured polyethyleneimines (LPEI). Transmission electron microscopy (TEM) analysis showed that the obtained N&ndash, CDs had an average size of 3.4 nm. The N&ndash, CDs were monodispersed in aqueous solution and were strongly fluorescent under the irradiation of ultra-violet light. A detailed description of the morphology and shape was established using Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). It was shown that LPEI were successfully tuned the fluorescence (PL) properties of CDs in both the intrinsic and surface electronic structures, and enhanced the quantum yield (QY) up to 44%. The obtained N&ndash, CDs exhibited remarkable PL stability, long lifetime and pH-dependence behaviour, with the excitation/emission maxima of 350/465.5 nm. Impressively, PL enhancement and blue-shifted emission could be seen with the dilution of the original N&ndash, CDs solution. The obtained N&ndash, CDs were further applied as fluorescent probe for the identification of Cu2+ in aqueous media. The mechanism could be attributed to the particularly high thermodynamic affinity of Cu2+ for the N-chelate groups over the surface of N&ndash, CDs and the fast metal-to-ligand binding kinetics. The linear relationship between the relative quenching rate and the concentration of Cu2+ were applied between 1&ndash, 30 &micro, M, with a detection limit of 0.93 &micro, M. The fluorescent probe was successfully applied for the detection of Cu2+ in real water. Moreover, a solid-state film of N&ndash, CDs was prepared in the presence of poly (vinyl alcohol) (PVA) polymer and found to be stable even after 72-h of continuous irradiation to UV-lamp. In contrast to the aqueous N&ndash, CDs, the composite film showed only an excitation independent property, with enhanced PL QY of around 47%. Due to the strong and stable emission nature of N&ndash, CDs in both aqueous and solid conditions, the obtained N&ndash, CDs are ideal for reducing the overall preparation costs and applying them for various biological and environmental applications in the future.

1st International Postgraduate Conference on Mechanical Engineering (IPCME) -- OCT 31, 2018 -- Univ Malaysia Pahang, Pahang, MALAYSIA Temitope, Dele-Afolabi/0000-0003-0187-9208; Sobri, Shafreeza/0000-0002-5675-2186 WOS: 000461178900019 In this study, the effect of nickel (Ni) addition on the microstructure and corrosion resistance properties of porous alumina (Al2O3) composites shaped with sugarcane bagasse pore-forming agent were evaluated. Plain and Ni-reinforced porous alumina sampels (Al2O3-xNi-RH; x = 2, 4, 6 and 8wt%) were prepared using the powder metallurgy method. Experimental results showed that the porosity (50.4-57.1vol%) and the pore size (62-109 mu m) of the porous alumina composites increased with rising content of Ni reinforcement. The XRD results showed that the Al2O3 matrix and Ni reinforcement reacted during the heat treatment process to produce nickel aluminate (NiAl2O4) spinel. Corrosion resistance results showed that the porous alumina composites exhibited better chemical stability in strong alkali solution as compared with strong acid solution. Univ Malaysia Pahang, Fac Mech Engn, Pekan Campus

In this study, the performance of glyphosate removal in an electrocoagulation batch with two electrodes formed by the same metal type, consisting of aluminum, iron, steel and copper have been compared. The aim of this study intends to remove glyphosate from an aqueous solution by an electrocoagulation process using metal electrode plates, which involves electrogeneration of metal cations as coagulant agents. The production of metal cations showed an ability to bind together to form aggregates of flocs composed of a combination of glyphosate and metal oxide. Electrocoagulation using aluminum electrodes indicated a high percentage removal of glyphosate, 94.25%; followed by iron electrodes, 88.37%; steel electrodes, 62.82%; and copper electrodes, 46.69%. The treated aqueous solution was then analyzed by Fourier Transform Infrared Spectroscopy. Percentages of Carbon, Hydrogen, Nitrogen, Sulfur remaining in the treated aqueous solution after the electrocoagulation process have been determined. The treated water and sludge were characterized and the mechanism of the overall process was concluded as an outcome. An X-Ray Diffraction analysis of dried sludge confirmed that new polymeric compounds were formed during the treatment. The sludge composed of new compounds were also verified the removals. This study revealed that an electrocoagulation process using metal electrodes is reliable and efficient.

Most developing countries in the world face the common challenges of reducing air pollution and advancing the process of sustainable development, especially in China. Air pollution research is a complex system and one of the main methods is through numerical simulation. The air quality model is an important technical method, it allows researchers to better analyze air pollutants in different regions. In addition, the SCB is a high-humidity and foggy area, and the concentration of atmospheric pollutants is always high. However, research on this region, one of the four most polluted regions in China, is still lacking. Reviewing the application of air quality models in the SCB air pollution has not been reported thoroughly. To fill these gaps, this review provides a comprehensive narration about i) The status of air pollution in SCB; ii) The application of air quality models in SCB; iii) The problems and application prospects of air quality models in the research of air pollution. This paper may provide a theoretical reference for the prevention and control of air pollution in the SCB and other heavily polluted areas in China and give some1inspirations for air pollution forecast in other countries with complex terrain.

Molecular dynamics (MD) simulation is a powerful tool to study the molecular level working mechanism of corrosion inhibitors in mitigating corrosion. In the past decades, MD simulation has emerged as an instrument to investigate the interactions at the interface between the inhibitor molecule and the metal surface. Combined with experimental measurement, theoretical examination from MD simulation delivers useful information on the adsorption ability and orientation of the molecule on the surface. It relates the microscopic characteristics to the macroscopic properties which enables researchers to develop high performance inhibitors. Although there has been vast growth in the number of studies that use molecular dynamic evaluation, there is still lack of comprehensive review specifically for corrosion inhibition of organic inhibitors on ferrous metal in acidic solution. Much uncertainty still exists on the approaches and steps in performing MD simulation for corrosion system. This paper reviews the basic principle of MD simulation along with methods, selection of parameters, expected result such as adsorption energy, binding energy and inhibitor orientation, and recent publications in corrosion inhibition studies.

In recent years, industrial sectors are concerned with the corrosion of metal and alloys and they also received huge attention from researcher to overcome these problems. To decelerate the rate of corrosion or to stop the corrosion to occur, one of the common methods to deal with this problems is using green inhibitor. The use of local wastes which are organic in nature for the production of green corrosion inhibitor is no doubt the trend of the day. To arrive at an inexpensive non-toxic, eco-friendly inhibitor formulation, the present study on the use of coconut pulp waste extract of Cocon Nucifera L. has been carried out by the weight loss method. The aim of this project is to study the inhibitive effect in terms of time and concentration of the coconut pulp waste extract on the acid corrosion of mild steel in 1.0 M HCL solution. Result showed that the inhibition efficiency was found to increase with increasing inhibitor concentration up to maximum 94.52% for 10 %v/v at 48 hours immersion time. Examination on the extract by Fourier transform infrared spectroscopy (FTIR) confirms that the extract contains functional group of N-H, O-H, C-H, C≡C, C=O, C=C, C-F and C-O that good for corrosion inhibitor while scanning electron microscopy (SEM) studies showed that the deposition of coconut pulp extract on the metal surface. The results of all studies confirmed that the extract of coconut pulp has great potential to prevent the corrosion of mild steel in acidic environment with highest % IE is 94.52 % and the corrosion rate is 3.6919 x10-5.

Temitope, Dele-Afolabi/0000-0003-0187-9208; Sobri, Shafreeza/0000-0002-5675-2186; Mazlan, Norkhairunnisa/0000-0003-0144-8360 WOS: 000402584900028 The strength integrity and chemical stability of porous alumina ceramics operating under extreme service conditions are of major importance in understanding their service behavior if they are to stand the test of time. In the present study, the effect of porosity and different pore former type on the mechanical strength and corrosion resistance properties of porous alumina ceramics have been studied. Given the potential of agricultural wastes as pore-forming agents (PFAs), a series of porous alumina ceramics (Al2O3-xPFA; x=5, 10, 15 and 20 wt%) were successfully prepared from rice husk (RH) and sugarcane bagasse (SCB) through the powder metallurgy technique. Experimental results showed that the porosity (44-67%) and the pore size (70-178 mu m) of porous alumina samples maintained a linear relationship with the PFA loading. Comprehensive mechanical strength characterization of the porous alumina samples was conducted not just as a function of porosity but also as a function of the different PFA type used. Overall, the mechanical properties showed an inverse relationship with the porosity as the developed porous alumina samples exhibited tensile and compressive strengths of 20.4-1.5 MPa and 179.5-10.9 MPa respectively. Moreover, higher strengths were observed in the SCB shaped samples up to the 15 wt% PFA mark, while beyond this point, the silica peak observed in the XRD pattern of the RH shaped samples favored their relatively high strength. The corrosion resistance characterization of the porous alumina samples in hot 10 wt% NaOH and 20 wt% H2SO4 solutions was also investigated by considering sample formulations with 5-15 wt% PFA addition. With increasing porosity, the mass loss range in RH and SCB shaped samples after corrosion in NaOH solution for 8 h were 1.25-3.6% and 0.44-2.9% respectively; on the other hand, after corrosion in H2SO4 solution for 8 h, the mass loss range in RH and SCB shaped samples were 0.62-1.5% and 0.68-3.3% respectively. Research Management Center of Universiti Putra Malaysia [GP-IPS/2016/9486500] The authors are thankful to the Research Management Center of Universiti Putra Malaysia for providing financial support (GP-IPS/2016/9486500) to carry out this research study. The authors also acknowledge the Department of Metallurgy and Materials Engineering, Kirikkale University, Turkey for the ongoing partnership, endless support and fruitful feedback.

An improved and alternative method for the extraction of the active coagulant agent from Jatropha curcas seeds was developed and compared with the conventional water extraction method (JCSC-DW). In the new method, the seeds were extracted using different solvents in different concentrations, using NaCl (JCSC-NaCl) and NaOH (JCSC-NaOH) to extract the active coagulant agent from the Jatropha. In addition, ultrasound was investigated as a potential method to assist the extraction process. Batch coagulation experiments were conducted to evaluate the performance of the extracted coagulant achieved through various schemes. The effects of the dosage, pH and concentration of solvents were investigated for optimum turbidity removal at different values of initial synthetic wastewater turbidity from 50 to 500 NTU. JCSC-NaCl at 0.5 M was found to provide a high turbidity removal of >99% compared to JCSC-DW and JCSC-NaOH at pH 3 using 120 mg/l of the coagulant agent. Among these three solvents, NaOH demonstrated the lowest performance in turbidity removal. The conventional extraction method of the active coagulant agent by blending the seeds in solvents for 2 min alone sufficiently extracts most of the coagulant component from the Jatropha seed and provides up to 99.4% turbidity removal. Blending assisted by ultrasound demonstrated comparable turbidity removal in a shorter period of time and thus showed a potential to be used on a larger scale. Analysis was undertaken to determine the protein content as this is believed to be the coagulating agent. It was found that extraction of the coagulant agent using NaCl yielded more protein compared to when using water and NaOH.

In this work, the adsorption effect of volatile organic compounds (chloroacetophenone, acetonitrile and hexane) towards the change of resistance of CNTs pellet as sensor signal was investigated. CNTs used in this research were synthesized using Floating Catalyst – Chemical Vapor Deposition (FC-CVD) method in optimum condition. The synthesized CNTs were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Raman Spectroscopy. The variation of resistance changes towards the tested gases were recorded using a multimeter. CNTs sensor pellet showed good responses towards the tested gases, however, the sensitivity, response time and recovery time of sensor pellet need to be optimized.

A potential low cost and environmentally friendly supercapacitor has been prepared from Palm Kernel Shell Biochar (PKSB). In this study, physical and electrochemical properties of raw, activated and chemical treated (potassium hydroxide (KOH)) as supercapacitors such as high carbon content, high charge storage capacity and stable were evaluated. For physical analyses, the scanning electron microscopy (SEM) was used to study the surface morphology and surface area and porosity were measured using Brunaurer-Emmert-Teller (BET). The chemical treated PKSB shows the highest surface area values of 55.15 m2/g as compared to raw and activated samples with surface area are 0.17 m2/g and 19.32 m2/g, respectively. This is verified by in enhancement of capacitance achieved from 1.76 × 10−3 Fg-1 for the activated biochar and 1.87 × 10−6 Fg-1 for untreated PKSB showed by Raman spectroscopy. This enhancement reflected the charge storage capacity is attributed to the creation of broad distribution in pore size and a larger surface area. In addition, this phenomenon also supported by the electrochemical profiles through cyclic voltammogram (CV) measured by Potentiostat-Gavanostat (EIS). CV of the treated PKSB gave better square shape than the activated and raw biochar samples. These characterizations conclude that the raw palm kernel biochar need further treatment to become supercapacitor electrodes to replace activated carbon.

Multi walled carbon nanotubes (MWCNTs) were synthesized using floating catalyst-chemical vapor deposition (FC-CVD) with ferrocene and benzene as catalyst and carbon source, respectively. Argon was used as a purging gas while hydrogen was used as a carrier gas. Hydrogen flow rate, reaction time and reactor temperature were varied to obtain high yield and purity of MWCNTs. The morphology and microstructures of MWCNTs produced were studied using Scanning Electron Microscopy (SEM). It was found that the maximum yield and purity of MWCNTs were produced at hydrogen flow rate of 300 ml/min with reactor temperature of 900°C and reaction time 45 minutes. It was observed that the MWCNTs are film-like, randomly oriented and in some cases entangled with uniform diameter.

This study was intended to compare the performance of electrocoagulation process using aluminium and iron electrodes for glyphosate removal in aqueous solution. The effects of initial glyphosate concentration, electrocoagulation time and distance between electrodes, were discussed in detail. An electrocoagulation tank of 500mL with two metal plates electrodes, same in dimensions and metal types, was set up to perform batch mode laboratory experiment and the glyphosate in white powder was first diluted with deionized water. Production of metal cations showed an ability to neutralize negatively charged particles, which then encouraged to bind together to form aggregates of flocs composed of a combination of glyphosate and metal hydroxide. Compared with iron electrodes, aluminium electrodes were more effective for glyphosate removal, with a removal efficiency of over than 80%. This study revealed that electrocoagulation process using aluminium electrodes is reliable, especially designed for initial concentration 100 mg/L, electrocoagulation time 50 min, and distance between electrodes 6 cm. Finally, it can be concluded that electrocoagulation process using aluminium electrodes is efficient for glyphosate removal from aqueous environments.

This research was carried out to investigate the effect of gas adsorption towards the electrical resistance of carbon nanotubes (CNTs) thin film. CNTs were synthesized by Floating Catalyst Chemical Vapor Deposition (FC-CVD) method on quartz substrate at 950°C under methane gas flow rate of 150 Standard Cubic Centimeters per Minute (SCCM). Then, the electrical resistance of CNTs was measured by exposing the sensors to CO2 and CH4 gases operating at room temperature. The sensors showed high responses to the gaseous molecules. In the same experimental conditions, the recovery of the sensors was different for CO2 and CH4. It was also observed that the CNTs device behaves as a p-type semiconductor when exposed to gaseous molecules. The fabrication process was relatively simple and did not require special techniques.

This research was carried out to monitor and investigate the gas sensing effects on carbon nanotubes (CNTs) by a systematic study of the variations in the electrical resistance as sensor signal induced by adsorption of CO2 and CH4 gaseous molecules. The CNTs were synthesized by Floating Catalyst Chemical Vapor Deposition (FC-CVD) method on quartz substrate under benzene bubble at temperature of 700°C. Then, they were tested for gas sensing applications operating at room temperature. Upon exposure to gaseous molecules, the electrical resistance of CNTs dramatically increased for both CO2 and CH4 gases with short response time and high sensitivity. It was also observed that the CNTs device behaves as a p-type semiconductor when exposed to gaseous molecules. In addition, the recovery of the sensors and mechanism of gas sensing procedure are discussed.

An attempt was made to investigate the removal of Escherichia coli bacteria from drinking water using nano silver-coated polypropylene water filter. For the production of nano silver filters, a modified Balzers 760 machine equipped with an electron beam gun was used. The nano-silver particles were made by electron beam bombardment of the silver metal, which were subsequently deposited on the polypropylene filters evenly. The thickness of the nano layer coated on the filters was 35.0 nm. The nano silver-coated filters were characterized using scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and atomic force microscopy. The antibacterial efficiency of the filters was evaluated using the membrane filter method. At a flow rate of 3 l/h, the output count of E. coli was zero after 7 h filtration when the input water had a bacterial load of 103 colony-forming units (cfu) per milliliter. The inductively coupled plasma/mass spectrometry (ICP/MS) results showed that the 35 nm layer of the silver nanoparticles were stable on the water filter and were not washed away by water flow even after 72 h.

This study has been initiated to improve the time taken by the CPF method and eliminate the convergence problem for the tested system by enforcing the General Minimal Residual (GMRES) method at the initial point at the start up, herewith referred as CPF-GMRES solver. Analyses have shown that this new algorithm not only reduced the computation time but also eliminated the convergence problem for the tested system.

A solution containing thiosulphate and sulphite has been developed specially for microelectronics applications to replace the conventional cyanide-based bath for long-term sustainability of gold electroplating. However, at the end of the electrodeposition process, the spent electrolyte can contain a significant amount of gold in solution. Investigations have been done to study the feasibility of gold recovery from the spent thiosulphate-sulphite electrolyte. In a previous work, flat plate glassy carbon was used to study the initial nucleation mechanism of gold deposition. However, in that study the growth of nuclei or their eventual formation into a gold film was not examined. Here, we present the microscopy observations of crystal growth of gold on glassy carbon at longer deposition times as a function of deposition potentials. It was found that the initial deposition of gold at low-cathodic potential corresponds to an electrochemical diffusion controlled gold discharge from which spherical nuclei are obtained. After a certain time the initial growing nuclei become unstable and the thin gold deposit begins to develop tips, which eventually grow larger and produce dendrites. The dendritic growth is controlled by surface-diffusion limitations of gold.

Interest has grown in developing non-toxic electrolytes for gold electrodeposition to replace the conventional cyanide- based bath for long term sustainability of gold electroplating. One such alternative electrolyte is a solution containing thiosulphate and sulphite, which has been developed specially for microelectronics applications. However, at the end of the electrodeposition process, the spent electrolyte contains a significant amount of gold. This study has been initiated to investigate the feasibility of gold recovery from a spent thiosulphate-sulphite electrolyte.

Electrodeposition of soft gold is an important process in the fabrication of micro devices for electronics, optics etc. Traditional gold electroplating is based on a gold cyanide process which is not applicable for the stringent requirements in state of the art micro device manufacture. Newcastle University has been involved in the development of an industrial process based on a mixed ligand electrolyte—the gold thiosulphate–sulphite system. Here we present methods for the formulation of this electrolyte in the laboratory which ensure bath stability and process compatibility. In addition, we have carried out spectrophotometry to elucidate the possible reasons of its chemical stability. Standard rotating disk and cyclic voltammetry has been carried out to determine the electrochemical behaviour of the gold thiosulphate–sulphite system. The changes in electrochemical behaviour as the bath ages are also discussed.

Herbicide has been widely used since it was first marketed. Consumption of water contains glyphosate herbicide can bring adverse effects to human health. This study was intended to evaluate the performance of electrocoagulation process using copper electrodes for glyphosate removal in aqueous solution. Synthetic glyphosate powder has been diluted in deionized water. An electrocoagulation tank of 500 mL with two copper plates electrodes, same in dimensions were setup. The effects of continuous variables of initial glyphosate concentration, electrocoagulation time and current density, were discussed in detail. Production of copper cations showed an ability to neutralize negatively charged particles, then, encouraged to bind together to form aggregates of flocs composed of a combination of glyphosate and copper hydroxide. This study revealed that electrocoagulation process using copper electrodes is reliable by indicating 46.69% glyphosate removal. Finally, it can be concluded that electrocoagulation process using copper electrodes is efficient for glyphosate removal from aqueous environments.

The research conducted a study on decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process. The purposes of this research are to remove pollutant through decomposition and to enhance the biodegradability of textile wastewater. The wastewater is treated using electron beam irradiation as a pre-treatment before undergo an activated sludge process. As a result, for non-irradiated wastewater, the COD removal was achieved to be between 70% and 79% after activated sludge process. The improvement of COD removal efficiency increased to 94% after irradiation of treated effluent at the dose of 50 kGy. Meanwhile, the BOD5 removal efficiencies of non-irradiated and irradiated textile wastewater were reported to be between 80 and 87%, and 82 and 99.2%, respectively. The maximum BOD5 removal efficiency was achieved at day 1 (HRT 5 days) of the process of an irradiated textile wastewater which is 99.2%. The biodegradability ratio of non-irradiated wastewater was reported to be between 0.34 and 0.61, while the value of biodegradability ratio of an irradiated wastewater increased to be between 0.87 and 0.96. The biodegradability enhancement of textile wastewater is increased with increasing the doses. Therefore, an electron beam radiation holds a greatest application of removing pollutants and also on enhancing the biodegradability of textile wastewater.

Manufacturing of PCBs is highly complicated and involves many processes. Recycling of PCB wastewater receives wide concerns as the recent international growth in the electronics industry has generated a drastic increase in the amount of waste PCBs with profound environmental impacts such as soil and groundwater contamination. This paper reports on the chemical characterization of PCB wastewater as the initial investigation for selective metal recovery.

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Although there are several electrolytes in the market for gold electrodeposition, a thiosulfate-sulfite mixed ligand bath has been recently developed specially for microelectronics applications. The main driver for the development of this electrolyte is long-term sustainability. At the end of a gold electrodeposition process, the spent electrolyte can contain a significant amount of gold in solution. This study has been initiated to study the feasibility of gold recovery from a used thiosulfate-sulfite electrolyte. In our work, we have used glassy carbon and graphite as electrodes. The two different forms of carbon were chosen due to the difference in their structures. It was found that at the early stages of the reduction process, the deposition of gold on glassy carbon exhibits an instantaneous nucleation. At longer times, the deposition follows the classical progressive nucleation phenomenon. Deposition of gold on graphite does not follow the classical nucleation phenomenon. Particle sizes and density can be controlled by varying the deposition potentials and time. This work is expected to elucidate information on the electrochemical behavior of a spent electrolyte at carbon electrodes, as well as studying their microstructural properties, which is likely to govern the utility of recovered gold.