Journal Articles

;

Kamarudin Hussin

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Mohamed Bnhussain

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Khairul Nizar Ismail

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Zarina Yahya

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Rafiza Abdul Razak

In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity.

3 15

Publication

Optimization of NaOH molarity, LUSI mud/alkaline activator, and Na₂SiO₃/NaOH ratio to produce lightweight aggregate-based geopolymer

( 2015)

Rafiza Abd Razak

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;

Djwantoro Hardjito

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Kamarudin Hussin

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Khairul Azwan Ismail

;

Zarina Yahya

This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na₂SiO₃/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

1 15

Publication

Analysis of short time period of operation of horizontal ground heat exchangers

( 2015)

Salsuwanda Selamat

;

Akio Miyara

;

Keishi Kariya

Ground source heat pump (GSHP) systems have been proven to have higher efficiency compared to conventional air source heat pump systems for space heating and cooling applications. While vertical ground heat exchangers (GHE) are favorable in GSHP installation, this type of configuration requires higher capital costs as opposed to horizontal configuration. Numerical simulation has been used to accurately predict the thermal performance of GHE. In this paper, numerical analysis of thermal performance for slinky horizontal GHE loops in different orientations and operation modes is discussed. It was found that the loop orientation is not so important due to the little effect it has on thermal performance. While the mean heat exchange rate of copper loop increases 48% compared to HDPE loop, the analysis supports the common claim that heat exchange rate is predominantly limited by the thermal conductivity of the ground. With the same amount of circulation work, the mean heat exchange rate increases by 83%–162% when operated in parallel loops operations. The performance in these operations can be further optimized to 10%–14% increase when spacing between adjacent loops was provided. The spacing helps to minimize interference of heat flow that would penalize the overall thermal performance.

6 6

Publication

A proposed aerobic granules size development scheme for aerobic granulation process

( 2015-04)

Farrah Aini Dahalan

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Norhayati Abdullah

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Ali Yuzir

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Gustaf Olsson

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Myzairah Salmiati

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Mohd Fadhil Mohd Hamdzah

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Siti Aqlima Din

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Khalilah Abdul Ahmad

;

Aznah Nor Khalil

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Zainura Zainon Anuar

;

Zaini Noor

Aerobic granulation is increasingly used in wastewater treatment due to its unique physical properties and microbial functionalities. Granule size defines the physical properties of granules based on biomass accumulation. This study aims to determine the profile of size development under two physicochemical conditions. Two identical bioreactors namely Rnp and Rp were operated under non-phototrophic and phototrophic conditions, respectively. An illustrative scheme was developed to comprehend the mechanism of size development that delineates the granular size throughout the granulation. Observations on granules’ size variation have shown that activated sludge revolutionised into the form of aerobic granules through the increase of biomass concentration in bioreactors which also determined the changes of granule size. Both reactors demonstrated that size transformed in a similar trend when tested with and without illumination. Thus, different types of aerobic granules may increase in size in the same way as recommended in the aerobic granule size development scheme.

Publication

Characterisation and evaluation of trimesic acid derivatives as disulphide cross-linked polymers for potential colon targeted drug delivery

( 2017)

Siti Nur Aishah Mat Yusuf

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Ng, Yoke Mooi

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Ayub, Asila Dinie

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Ngalim, Siti Hawa

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Vuanghao Lim

Discovery and use of biocompatible polymers offers great promise in the pharmaceutical field, particularly in drug delivery systems. Disulphide bonds, which commonly occur in peptides and proteins and have been used as drug-glutathione conjugates, are reductively cleaved in the colon. The intrinsic stability of a disulphide relative to thiol groups is determined by the redox potential of the environment. The objective of this study was to synthesise a trimesic acid-based disulphide cross-linked polymer that could potentially be used for targeted delivery to the colon. The monomer was synthesised by an amide coupling reaction between trimesic acid and (triphenylmethyl) thioethylamine using a two-step synthesis method. The s-trityl group was removed using a cocktail of trifluoroacetic acid and triethylsilane to expose the thiols in preparation for further polymerisation. The resulting polymers (P10, P15, P21, P25, and P51, generated using different molar ratios) were reduced after 1.5 h of reduction time. Scanning electron microscopy images of the polymers showed spherical, loose, or tight patterns depending on the molar ratio of polymerisation. These polymers also exhibited efficient dissolution under various gastrointestinal conditions. Of the five polymers tested, P10 and P15 appeared to be promising drug delivery vehicles for poorly soluble drugs, due to the hydrophobic nature of the polymers.

5 1

Publication

Prediction of pressuremeter modulus (E M) using GMDH neural network: a case study of Kenny Hill Formation

( 2020-05-01)

Mohd Faiz Mohammad Zaki

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Ismail M.A.M.

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Govindasamy D.

;

Leong F.C.P.

Soil investigation (SI) work is a process of collecting subsurface ground profile information in evaluating soil engineering properties for a construction project. The standard penetration method (SPT) is widely accepted worldwide as a feasible and relatively inexpensive method over other field tests. Pressuremeter test (PMT), on the other hand, is costly and more popular in situ method in interpreting soil deformation behavior. Considering SPT is available in almost site investigation works for all sizes of project, it was tempting to establish the correlation between SPT and PMT results, specifically in local geologic setting. The study was conducted in Kenny Hill Formation, Kuala Lumpur, Malaysia. The correlation established in this study is between pressuremeter modulus (EM) and SPT blow count (N60). In addition to in situ methods, the physical properties of soil extruded from boreholes were tested in geotechnical laboratories to determine soil properties, such as particle size distribution, liquid limit, and plastic limit. These parameters need to be considered during prediction of EM. Group method of data handling (GMDH) neural network has been used to achieve this objective. The mean absolute error (MAE) results show that the GMDH neural networks produce values of 8.04 and 8.59 for training and testing. The root mean square error (RMSE) yields 10.61 and 10.84 for training and testing, respectively. Further, the results of the coefficients of determination (R2) are 0.794 and 0.726 for training and testing demonstrates a good correlation exists between predicted and measured values. Based on the GMDH results, N60, sand, and clay are required input variables for determination of EM.

3 3

Publication

Assessment of the suitability of ceramic waste in geopolymer composites: an appraisal

( 2021)

Ismail Luhar

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Salmabanu Luhar

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Marcin Nabiałek

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Andrei Victor Sandu

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Janusz Szmidla

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Anna Jurczyńska

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Rafiza Abdul Razak

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Ikmal Hakem A Aziz

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Noorina Hidayu Jamil

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Laila Mardiah Deraman

Currently, novel inorganic alumino-silicate materials, known as geopolymer composites, have emerged swiftly as an ecobenevolent alternative to contemporary ordinary Portland cement (OPC) building materials since they display superior physical and chemical attributes with a diverse range of possible potential applications. The said innovative geopolymer technology necessitates less energy and low carbon footprints as compared to OPC-based materials because of the incorporation of wastes and/or industrial byproducts as binders replacing OPC. The key constituents of ceramic are silica and alumina and, hence, have the potential to be employed as an aggregate to manufacture ceramic geopolymer concrete. The present manuscript presents a review of the performance of geopolymer composites incorporated with ceramic waste, concerning workability, strength, durability, and elevated resistance evaluation.

Publication

Photocatalytic degradation of sugarcane vinasse using ZnO photocatalyst: operating parameters, kinetic studies, phytotoxicity assessments, and reusability

( 2021)

Kee Wei Chin

;

Wong Yee Shian

;

Ong Soon An

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Nabilah Aminah Lutpi

;

Sam Sung Ting

;

Audrey Chai Yee Chieh

;

Kim-Mun Eng

Photocatalytic degradation performance is highly related to optimized operating parameters such as initial concentration, pH value, and catalyst dosage. In this study, the impact of various parameters on the photocatalytic degradation of anaerobi‑ cally digested vinasse (AnVE) has been determined through decolourization and chemical oxygen demand (COD) reduction efciency using zinc oxide (ZnO) photocatalyst. In this context, the application of photocatalytic degradation in treating sugarcane vinasse using ZnO is yet to be explored. The COD reduction efciency and decolourization achieved 83.40% and 99.29%, respectively, under the conditions of 250 mg/L initial COD concentration, pH 10, and 2.0 g/L catalyst dosage. The phytotoxicity assessment was also conducted to determine the toxicity of AnVE before and after treatment using mung bean (Vigna radiata). The reduction of root length and the weight of mung bean indicated that the sugarcane vinasse contains enormous amounts of organic substances that afect the plant's growth. The toxicity reduction in the AnVE solution can be proved by UV–Vis absorption spectra. Furthermore, the catalyst recovery achieved 93% in the reusability test. However, the COD reduction efciency and decolourization were reduced every cycle. It was due to the depletion of the active sites in the catalyst with the adsorption of organic molecules. Thus, it can be concluded that the photocatalytic degradation in the treatment of AnVE was efective in organic degradation, decolorization, toxicity reduction and can be reused after the recovery process.

28 88

Publication

Mechanical properties of Fly Ash-Based geopolymer concrete incorporation Nylon66 Fiber

( 2022)

Muhd Hafizuddin Yazid

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Meor Ahmad Faris bin Meor Ahmad Tajudin

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Muhammad Shazril I. Ibrahim

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Rafiza Abdul Razak

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Dumitru Doru Burduhos Nergis

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Diana Petronela Burduhos Nergis

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Omrane Benjeddou

;

Khanh-Son Nguyen

This study was carried out to investigate the effect of the diamond-shaped Interlocking Chain Plastic Bead (ICPB) on fiber-reinforced fly ash-based geopolymer concrete. In this study, geopolymer concrete was produced using fly ash, NaOH, silicate, aggregate, and nylon66 fibers. Characterization of fly ash-based geopolymers (FGP) and fly ash-based geopolymer concrete (FRGPC) included chemical composition via XRF, functional group analysis via FTIR, compressive strength determination, flexural strength, density, slump test, and water absorption. The percentage of fiber volume added to FRGPC and FGP varied from 0% to 0.5%, and 1.5% to 2.0%. From the results obtained, it was found that ICBP fiber led to a negative result for FGP at 28 days but showed a better performance in FRGPC reinforced fiber at 28 and 90 days compared to plain geopolymer concrete. Meanwhile, NFRPGC showed that the optimum result was obtained with 0.5% of fiber addition due to the compressive strength performance at 28 days and 90 days, which were 67.7 MPa and 970.13 MPa, respectively. Similar results were observed for flexural strength, where 0.5% fiber addition resulted in the highest strength at 28 and 90 days (4.43 MPa and 4.99 MPa, respectively), and the strength performance began to decline after 0.5% fiber addition. According to the results of the slump test, an increase in fiber addition decreases the workability of geopolymer concrete. Density and water absorption, however, increase proportionally with the amount of fiber added. Therefore, diamond-shaped ICPB fiber in geopolymer concrete exhibits superior compressive and flexural strength.

11 2

Publication

Reclamation and Reutilization of Incinerator Ash in Artificial Lightweight Aggregate

( 2022)

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Roshazita, Che Amat

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Mustaqqim, Abdul Rahim

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Nur Liza, Rahim

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Abdul Rahim, Abdul Razak

This study focused on the reclamation of ash from incineration process and development of new artificial lightweight aggregate (LWA) that have comparable properties with existing natural coarse aggregate. The main objective of this study is to examine potential use of recycled municipal solid waste incineration (MSWI) ash as raw material in LWA production with a method of cold-bonded pelletization. Two types of incineration ash which is bottom ash (BA) and fly ash (FA) were collected from Cameron Highland Incineration Plant, Malaysia. The properties of BA and FA are studied by means of X-Ray Fluorescence (XRF) and microstructure of these ashes were inspected using Scanning Electron Microscope (SEM). The properties of BALA and FALA produced in this study is examined including loose bulk density, water absorption and aggregate impact value (AIV). From the results of both types of artificial LWA, the lowest loose bulk density of BALA is BALA50 with 564.14 kg/m3 and highest is at 831.19 kg/m3 . For FALA50, lowest loose bulk density is 573.64 kg/m3 and highest is 703.35 kg/m3 . Water absorption of BALA and FALA is quite similar with one another in with the value of 23.8% and 22.6%, respectively. Generally, FALA have better qualities of LWA comparing with BALA with lower bulk density and water absorption and can be categorized as strong aggregate. In summary, reclamation and reutilization of incinerator ash has generated acceptable qualities for artificial LWA. Both types of BA and FA shown a great potential to be recycled as additional materials in artificial aggregate production.

19 16

Publication

Metakaolin/sludge based geopolymer adsorbent on high removal efficiency of Cu2+

( 2022)

Pilomeena Arokiasamy

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Shayfull Zamree Abd. Rahim

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Mohd Remy Rozainy Mohd Arif Zainol

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Mohd Arif Anuar Mohd Salleh

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Marwan Kheimi

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Jitrin Chaiprapa

;

Andrei Victor Sandu

;

Petrica Vizureanu

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Rafiza Abd Razak

;

Noorina Hidayu Jamil

Activated carbon (AC) has received a lot of interest from researchers for the removal of heavy metals from wastewater due to its abundant porous structure. However, it was found unable to meet the required adsorption capacity due to its amorphous structure which restricts the fundamental studies and structural optimization for improved removal performance. In addition, AC is not applicable in large scale wastewater treatment due its expensive synthesis and difficulty in regeneration. Thus, the researchers are paying more attention in synthesis of low cost geopolymer based adsorbent for heavy metal removal due its excellent immobilization effect. However, limited studies have focused on the synthesis of geopolymer based adsorbent for heavy metal adsorption by utilizing industrial sludge. Thus, the aim of this research was to develop metakaolin (MK) based geopolymer adsorbent with incorporation of two types of industrial sludge (S1 and S3) that could be employed as an adsorbent for removing copper (Cu2+) from aqueous solution through the adsorption process. The effects of varied solid to liquid ratio (S/L) on the synthesis of metakaolin/sludge based geopolymer adsorbent and the removal efficiency of Cu2+ by the synthesis adsorbent were studied. The raw materials and synthesized geopolymer were characterized by using x-ray fluorescence (XRF), x-ray diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and micro XRF. The concentration of Cu2+ before and after adsorption was determined by atomic absorption spectroscopy (AAS) and the removal efficiency was calculated. The experimental data indicated that the synthesized geopolymer at low S/L ratio has achieved the highest removal efficiency of Cu2+ about 99.62 % and 99.37 % at 25 %:75 % of MK/S1 and 25 %:75 % of MK/S3 respectively compared to pure MK based geopolymer with 98.56 %. The best S/

2 8

Publication

Reclamation and Reutilization of Incinerator Ash in Artificial Lightweight Aggregate

( 2022-01-01)

;

Roshazita Che Amat

;

Mustaqqim Abdul Rahim

;

Nur Liza Rahim

;

Abdul Rahim Abdul Razak

This study focused on the reclamation of ash from incineration process and development of new artificial lightweight aggregate (LWA) that have comparable properties with existing natural coarse aggregate. The main objective of this study is to examine potential use of recycled municipal solid waste incineration (MSWI) ash as raw material in LWA production with a method of cold-bonded pelletization. Two types of incineration ash which is bottom ash (BA) and fly ash (FA) were collected from Cameron Highland Incineration Plant, Malaysia. The properties of BA and FA are studied by means of X-Ray Fluorescence (XRF) and microstructure of these ashes were inspected using Scanning Electron Microscope (SEM). The properties of BALA and FALA produced in this study is examined including loose bulk density, water absorption and aggregate impact value (AIV). From the results of both types of artificial LWA, the lowest loose bulk density of BALA is BALA50 with 564.14 kg/m3and highest is at 831.19 kg/m3. For FALA50, lowest loose bulk density is 573.64 kg/m3and highest is 703.35 kg/m3. Water absorption of BALA and FALA is quite similar with one another in with the value of 23.8% and 22.6%, respectively. Generally, FALA have better qualities of LWA comparing with BALA with lower bulk density and water absorption and can be categorized as strong aggregate. In summary, reclamation and reutilization of incinerator ash has generated acceptable qualities for artificial LWA. Both types of BA and FA shown a great potential to be recycled as additional materials in artificial aggregate production.

3 1

Publication

Tailoring the properties of calcium modified fibrous mesoporous silica KCC-1 for optimized sulfur dioxide removal

( 2022-01-01)

Muhammad Adli Hanif

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Khairuddin Md Isa

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Fahmi Muhammad Ridwan

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Tuan Abdullah T.A.

;

Jalil A.A.

Dry regenerative flue gas desulfurization (FGD) is a promising method to tackle industrial issues regarding SO2 emission into the atmosphere due to its sorbent being highly accessible, the lack of water dependency and reduction in waste management. This study examined the feasibility of using fibrous mesoporous silica KCC-1 which has been reported to possess better properties than several other predecessor mesoporous silica as alternative sorbents for dry FGD. Calcium metal was introduced to overcome the lack of active sites available on KCC-1 while simultaneously providing sufficient basicity to counter the increase in acidity brought by SO2 adsorption. Three sorbent modification parameters were analyzed: metal loading (5–15 wt %), calcination temperature (823–973 K) and calcination time (5.5–7 h), and the prepared samples were characterized using BET surface area and pore analyzer, FESEM-EDX, XRD and H2-TPR. The breakthrough experiment was conducted using a lab scale fixed bed reactor system with 1500 ppm SO2/N2 at 200 mL/min. SO2 removal was optimized by sorbent prepared with calcium loading of 5 wt %, calcination temperature of 923 K and calcination time of 6.5 h with adsorption capacity of 3241.94 mg SO2/g KCC-1. The optimized sorbent demonstrated highest surface area, good pore development, high dispersion of calcium metal, appropriate impregnation of calcium oxide which caused only minor distortion to the silica framework of KCC-1. Subjecting the optimized sample to five consecutive regeneration cycles by heating at 773 K while simultaneously flowing N2 gas for an hour shows good regeneration performance with a total final reduction of only 25% from the initial adsorption capacity obtained from a fresh sample.

1

Publication

The stiffness of steel-wood-steel connection loaded parallel to the grain

( 2022-01-01)

Nur Liza Rahim

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Raftery G.

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Quenneville P.

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Ing D.S.

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Nabialek M.

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Jaya R.P.

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;

;

Śliwa A.

In Eurocode 5, the stiffness equation for bolted steel-wood-steel is stated as a function of wood density and fastener diameter only. In this research, an experimental study on various configurations of tested bolted steel-wood-steel (SWS) connections has been undertaken to predict the initial stiffness of each connection. In order to validate the Eurocode 5 stiffness equation, tests on 50 timber specimens (40 glued laminated timbers and 10 laminated veneer lumbers (LVL)) with steel plates were undertaken. The number of bolts was kept similar and the connector diameter, timber thickness, and wood density were varied. The results obtained in the experimental tests are compared with those obtained from the Eurocode 5 stiffness equation. From the analysis, it is signified that the stiffness equation specified in Eurocode 5 for bolted SWS connections does not adequately predict the initial stiffness. The results from Eurocode 5 stiffness equation are very far from the experimental values. The ratio of stiffness equation to experimental results ranges from 3.48 to 4.20, with the average at 3.77, where the equation over-predicted the experimental stiffness value for the connection. There is a need to consider or incorporated other parameters such as geometric configurations in Eurocode 5 stiffness equation to improve the ratio with the experimental data.

2 3

Publication

A Properties of Municipal Solid Waste Incineration Fly Ash (IFA) And Cement Used in The Manufacturing of New Inventive Blended Cement

( 2022-01-01)

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Roshazita Che Amat

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Nur Liza Rahim

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Izzatul Nurain Che Sang Beri

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Syakirah Afiza Mohammed

;

Zailani W.W.A.

Municipal solid waste incinerator fly (IFA) ash is prone to accumulate high concentration heavy metals. Due to the increasing costs to treat remaining fly ash at the landfill, a lot of research has been done to recycle IFA. This study was focusing on the properties of IFA and cement as main raw materials in new inventive blended cement. The properties of blended cement were also being investigated. Properties of IFA and cement were examined through several test which includes density, specific gravity, X-Ray Fluorescence (XRF), Loss of Ignition (LOI) and through Toxicity Characteristic Leaching Procedure (TCLP) test. The density test and LOI test were also being done for the blended cement. From the tests for IFA and cement, it can be found that density the density of fly ash and cement that has been used for this study were found to be 0.76 g/cm3 and 3.67 g/cm3 respectively. Then, the specific gravity of fly ash and cement were 1.69 and 2.98, accordingly. XRF results shows that both materials have highest content of aluminium, silica and iron, as expected. LOI of fly ash and cement were found to be 17.33 % and 12.33 %, respectively. In terms of the leaching rates of heavy metals (Mn, Ni, Cd, Cr, Cu), only Cd leached at rate 2.39 mg/L, which is above the USEPA's regulatory level, 1.0 mg/L. 5 %, 10 % and 15 % of IFA was mixed with cement to produced blended cement. As the density of blended cement, it was found to be 1.12 g/cm3, 1.08 g/cm3 and 1.09 g/cm3 for each of 5 %, 10 % and 15 % of fly ash in blended cement.

4

Publication

Removal of naproxen using low-cost Dillenia Indica peels as an activated carbon

( 2022-01-01)

Fadirah Fadzail

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Masitah Hasan

;

Zulfakar Mokhtar

;

A batch adsorption process of naproxen (NPX) using activated carbon derived from Dillenia Indica peel was performed at the laboratory scale. NPX was selected as an adsorbate due to its toxicity and large occurrence in water. The study was conducted to examine the ability of prepared activated carbon in adsorbing the NPX. The adsorption was conducted at various initial concentrations of NPX, contact time, adsorbent dosage, and pH. Results of batch adsorption showed that the maximum adsorption was reached at lower pH and adsorbent dosage of 0.4 g. 8 h is needed for the adsorption to reached equilibrium. Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm have been used to analyse the properties of the adsorption process. The data are best suited for the Langmuir and Temkin isotherm and the adsorption follows a pseudo-second order model for kinetic study. The results suggest that the adsorption behave as a monolayer and the process is controlled by chemisorption mechanism. The adsorption capacity of 10.76 mg/g concluded that the activated carbon prepared from Dillenia Indica peel is effective in removing NPX from the water.

1

Publication

Photocatalytic Degradation of Sugarcane Vinasse Using ZnO Photocatalyst: Operating Parameters, Kinetic Studies, Phytotoxicity Assessments, and Reusability

( 2022-02-01)

Kee Wei Chin

;

Wong Yee Shian

;

Ong Soon An

;

Nabilah Aminah Lutpi

;

Sam Sung Ting

;

Audrey Chai Yee Chieh

;

Eng K.M.

Abstract: Photocatalytic degradation performance is highly related to optimized operating parameters such as initial concentration, pH value, and catalyst dosage. In this study, the impact of various parameters on the photocatalytic degradation of anaerobically digested vinasse (AnVE) has been determined through decolourization and chemical oxygen demand (COD) reduction efficiency using zinc oxide (ZnO) photocatalyst. In this context, the application of photocatalytic degradation in treating sugarcane vinasse using ZnO is yet to be explored. The COD reduction efficiency and decolourization achieved 83.40% and 99.29%, respectively, under the conditions of 250 mg/L initial COD concentration, pH 10, and 2.0 g/L catalyst dosage. The phytotoxicity assessment was also conducted to determine the toxicity of AnVE before and after treatment using mung bean (Vigna radiata). The reduction of root length and the weight of mung bean indicated that the sugarcane vinasse contains enormous amounts of organic substances that affect the plant's growth. The toxicity reduction in the AnVE solution can be proved by UV–Vis absorption spectra. Furthermore, the catalyst recovery achieved 93% in the reusability test. However, the COD reduction efficiency and decolourization were reduced every cycle. It was due to the depletion of the active sites in the catalyst with the adsorption of organic molecules. Thus, it can be concluded that the photocatalytic degradation in the treatment of AnVE was effective in organic degradation, decolorization, toxicity reduction and can be reused after the recovery process. Graphical abstract: [Figure not available: see fulltext.].

1 3

Publication

Microplastics and nanoplastics: Recent literature studies and patents on their removal from aqueous environment

( 2022-03-01)

Muhammad Adli Hanif

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;

Farrah Aini Dahalan

;

Umi Fazara Md Ali

;

Masitah Hasan

;

Jalil A.A.

The presence of microplastics (MP) and nanoplastics (NP) in the environment poses significant hazards towards microorganisms, humans, animals and plants. This paper is focused on recent literature studies and patents discussing the removal process of these plastic pollutants. Microplastics and nanoplastics can be quantified by counting, weighing, absorbance and turbidity and can be further analyzed using scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, surface-enhanced Raman spectroscopy and Raman tweezers. Mitigation methods reported are categorized depending on the removal characteristics: (i) Filtration and separation method: Filtration and separation, electrospun nanofiber membrane, constructed wetlands; (ii) Capture and surface attachment method: coagulation, flocculation and sedimentation (CFS), electrocoagulation, adsorption, magnetization, micromachines, superhydrophobic materials and microorganism aggregation; and (iii) Degradation method: photocatalytic degradation, microorganism degradation and thermal degradation; where removal efficiency between 58 and 100% were reported. As these methods are significantly distinctive, the parameters which affect the MP/NP removal performance e.g., pH, type of plastics, presence of interfering chemicals or ions, surface charges etc. are also discussed. 42 granted international patents related to microplastics and nanoplastics removal are also reviewed where the majority of these patents are focused on separation or filtration devices. These devices are efficient for microplastics up to 20 μm but may be ineffective for nanoplastics or fibrous plastics. Several patents were found to focus on methods similar to literature studies e.g., magnetization, CFS, biofilm and microorganism aggregation; with the addition of another method: thermal degradation.

1

Publication

Sulfur dioxide removal by calcium-modified fibrous KCC-1 mesoporous silica: kinetics, thermodynamics, isotherm and mass transfer mechanism

( 2022-04-01)

Muhammad Adli Hanif

;