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Fulltext Simple Response Surface Methodology: Investigation on Advance Photocatalytic Oxidation of 4-Chlorophenoxyacetic Acid Using UV-Active ZnO Photocatalyst

Lee KM, Hamid SBA

Materials (Basel), 2015 Jan 19;8(1):339-354.
PMID: 28787941 DOI: 10.3390/ma8010339

The performance of advance photocatalytic degradation of 4-chlorophenoxyacetic acid (4-CPA) strongly depends on photocatalyst dosage, initial concentration and initial pH. In the present study, a simple response surface methodology (RSM) was applied to investigate the interaction between these three independent factors. Thus, the photocatalytic degradation of 4-CPA in aqueous medium assisted by ultraviolet-active ZnO photocatalyst was systematically investigated. This study aims to determine the optimum processing parameters to maximize 4-CPA degradation. Based on the results obtained, it was found that a maximum of 91% of 4-CPA was successfully degraded under optimal conditions (0.02 g ZnO dosage, 20.00 mg/L of 4-CPA and pH 7.71). All the experimental data showed good agreement with the predicted results obtained from statistical analysis.
Fulltext Statistical Optimization for Acid Hydrolysis of Microcrystalline Cellulose and Its Physiochemical Characterization by Using Metal Ion Catalyst

Karim MZ, Chowdhury ZZ, Hamid SBA, Ali ME

Materials (Basel), 2014 Oct 13;7(10):6982-6999.
PMID: 28788226 DOI: 10.3390/ma7106982

Hydrolyzing the amorphous region while keeping the crystalline region unaltered is the key technology for producing nanocellulose. This study investigated if the dissolution properties of the amorphous region of microcrystalline cellulose can be enhanced in the presence of Fe(3+) salt in acidic medium. The process parameters, including temperature, time and the concentration of metal chloride catalyst (FeCl₃), were optimized by using the response surface methodology (RSM). The experimental observation demonstrated that temperature and time play vital roles in hydrolyzing the amorphous sections of cellulose. This would yield hydrocellulose with higher crystallinity. The factors that were varied for the production of hydrocellulose were the temperature (x₁), time (x₂) and FeCl₃ catalyst concentration (x₃). Responses were measured in terms of percentage of crystallinity (y₁) and the yield (y₂) of the prepared hydrocellulose. Relevant mathematical models were developed. Analysis of variance (ANOVA) was carried out to obtain the most significant factors influencing the responses of the percentage of crystallinity and yield. Under optimum conditions, the percentage of crystallinity and yield were 83.46% and 86.98% respectively, at 90.95 °C, 6 h, with a catalyst concentration of 1 M. The physiochemical characteristics of the prepared hydrocellulose were determined in terms of XRD, SEM, TGA and FTIR analyses. The addition of FeCl₃ salt in acid hydrolyzing medium is a novel technique for substantially increasing crystallinity with a significant morphological change.
Fulltext Base Catalytic Approach: A Promising Technique for the Activation of Biochar for Equilibrium Sorption Studies of Copper, Cu(II) Ions in Single Solute System

Hamid SBA, Chowdhury ZZ, Zain SM

Materials (Basel), 2014 Apr 09;7(4):2815-2832.
PMID: 28788595 DOI: 10.3390/ma7042815

This study examines the feasibility of catalytically pretreated biochar derived from the dried exocarp or fruit peel of mangostene with Group I alkali metal hydroxide (KOH). The pretreated char was activated in the presence of carbon dioxide gas flow at high temperature to upgrade its physiochemical properties for the removal of copper, Cu(II) cations in single solute system. The effect of three independent variables, including temperature, agitation time and concentration, on sorption performance were carried out. Reaction kinetics parameters were determined by using linear regression analysis of the pseudo first, pseudo second, Elovich and intra-particle diffusion models. The regression co-efficient, R² values were best for the pseudo second order kinetic model for all the concentration ranges under investigation. This implied that Cu(II) cations were adsorbed mainly by chemical interactions with the surface active sites of the activated biochar. Langmuir, Freundlich and Temkin isotherm models were used to interpret the equilibrium data at different temperature. Thermodynamic studies revealed that the sorption process was spontaneous and endothermic. The surface area of the activated sample was 367.10 m²/g, whereas before base activation, it was only 1.22 m²/g. The results elucidated that the base pretreatment was efficient enough to yield porous carbon with an enlarged surface area, which can successfully eliminate Cu(II) cations from waste water.
Fulltext Advanced Chemical Reduction of Reduced Graphene Oxide and Its Photocatalytic Activity in Degrading Reactive Black 5

Wong CPP, Lai CW, Lee KM, Hamid SBA

Materials (Basel), 2015 Oct 19;8(10):7118-7128.
PMID: 28793623 DOI: 10.3390/ma8105363

Textile industries consume large volumes of water for dye processing, leading to undesirable toxic dyes in water bodies. Dyestuffs are harmful to human health and aquatic life, and such illnesses as cholera, dysentery, hepatitis A, and hinder the photosynthetic activity of aquatic plants. To overcome this environmental problem, the advanced oxidation process is a promising technique to mineralize a wide range of dyes in water systems. In this work, reduced graphene oxide (rGO) was prepared via an advanced chemical reduction route, and its photocatalytic activity was tested by photodegrading Reactive Black 5 (RB5) dye in aqueous solution. rGO was synthesized by dispersing the graphite oxide into the water to form a graphene oxide (GO) solution followed by the addition of hydrazine. Graphite oxide was prepared using a modified Hummers' method by using potassium permanganate and concentrated sulphuric acid. The resulted rGO nanoparticles were characterized using ultraviolet-visible spectrophotometry (UV-Vis), X-ray powder diffraction (XRD), Raman, and Scanning Electron Microscopy (SEM) to further investigate their chemical properties. A characteristic peak of rGO-48 h (275 cm-1) was observed in the UV spectrum. Further, the appearance of a broad peak (002), centred at 2θ = 24.1°, in XRD showing that graphene oxide was reduced to rGO. Based on our results, it was found that the resulted rGO-48 h nanoparticles achieved 49% photodecolorization of RB5 under UV irradiation at pH 3 in 60 min. This was attributed to the high and efficient electron transport behaviors of rGO between aromatic regions of rGO and RB5 molecules.
Fulltext InSitu Anodization of WO₃-Decorated TiO₂ Nanotube Arrays for Efficient Mercury Removal

Lee WH, Lai CW, Hamid SBA

Materials (Basel), 2015 Aug 28;8(9):5702-5714.
PMID: 28793530 DOI: 10.3390/ma8095270

WO₃-decorated TiO₂ nanotube arrays were successfully synthesized using an in situ anodization method in ethylene glycol electrolyte with dissolved H₂O₂ and ammonium fluoride in amounts ranging from 0 to 0.5 wt %. Anodization was carried out at a voltage of 40 V for a duration of 60 min. By using the less stable tungsten as the cathode material instead of the conventionally used platinum electrode, tungsten will form dissolved ions (W(6+)) in the electrolyte which will then move toward the titanium foil and form a coherent deposit on the titanium foil. The fluoride ion content was controlled to determine the optimum chemical dissolution rate of TiO₂ during anodization to produce a uniform nanotubular structure of TiO₂ film. Nanotube arrays were then characterized using FESEM, EDAX, XRD, as well as Raman spectroscopy. Based on the FESEM images obtained, nanotube arrays with an average pore diameter of up to 65 nm and a length of 1.8 µm were produced. The tungsten element in the samples was confirmed by EDAX results which showed varying tungsten content from 0.22 to 2.30 at%. XRD and Raman results showed the anatase phase of TiO₂ after calcination at 400 °C for 4 h in air atmosphere. The mercury removal efficiency of the nanotube arrays was investigated by photoirradiating samples dipped in mercury chloride solution with TUV (Tube ultraviolet) 96W UV-B Germicidal light. The nanotubes with the highest aspect ratio (15.9) and geometric surface area factor (92.0) exhibited the best mercury removal performance due to a larger active surface area, which enables more Hg(2+) to adsorb onto the catalyst surface to undergo reduction to Hg⁰. The incorporation of WO₃ species onto TiO₂ nanotubes also improved the mercury removal performance due to improved charge separation and decreased charge carrier recombination because of the charge transfer from the conduction band of TiO₂ to the conduction band of WO₃.
'Eat Right, Future Bright: Nutrition Education Program' (ERFB-NEP) module for aboriginal primary school children in Malaysia

Nordin NA, Haris SN, Hamid SBA

J Educ Health Promot, 2023;12:11.
PMID: 37034863 DOI: 10.4103/jehp.jehp_744_22

BACKGROUND: Nutrition is essential for schoolchildren to reach their full potential psychologically and cognitively. Malnutrition, which is prevalent among aboriginal schoolchildren in Malaysia, can interfere their learning and academic performance. Developing a module to be used during a school-based nutritional intervention program is essential to ensuring that students develop healthy eating habits and lifestyles. Thus, this study aims to develop and validate nutrition education module focusing on aboriginal schoolchildren for the eat right future bright (ERFB) nutrition education program.
MATERIALS AND METHODS: This cross-sectional study was conducted in three steps: Step 1: development of module based on literature reviews, Step 2: content and face validation of the module by the expert panels, and Step 3: face validation of the module by target users. This study has used the validation form proposed by de Castro. This form consists of seven aspects, two aspects related to content validity and another four aspects related to face validity. A content validity index (CVI) was used to analyze the content validity. Two formulas were used to calculate CVI, which were I-CVI and S-CVI. Meanwhile, the data for module's face used the level of agreement.
RESULTS: Both I-CVI and S-CVI obtained more than 0.78 and 0.80, respectively, which indicate that the module has good content validity. Moreover, for face validity, the total of agreement from expert panels and target users was more than 75%, which is considered face validated.
CONCLUSIONS: In conclusion, the module that has been developed has good content validity and can be used by teachers in teaching appropriate nutrition knowledge to aboriginal primary schoolchildren.
Stunting and food insecurity among children from low socioeconomic family during COVID-19 pandemic in urban area in Selangor

Hamid SBA, Denil NM, Ismail NA, Mauludyani AVR

Med J Malaysia, 2024 Mar;79(Suppl 1):53-58.
PMID: 38555886

INTRODUCTION: Food insecurity is often link with nutritional status. An increased rate of food insecurity can have a severe impact on children's growth. During the COVID-19 outbreak, little is known regarding its effect on food security and nutritional status, especially concerning vulnerable groups such as children. The purpose of this study was to assess household food security status, children's nutritional status along with their association, and the determinants of food insecurity during the COVID-19 pandemic.
MATERIALS AND METHODS: This cross-sectional study was conducted from May to July 2022 in urban areas in Selangor among children aged less than two years old from B40 households using purposive sampling through both online surveys and face-to-face interviews. There were 112 children aged < 2 years old from B40 households participating in this study. The data obtained on maternal sociodemographic, Household Food Insecurity Scale (HFIAS), and children's anthropometric measurements were analysed by using the WHO Anthro Survey, descriptive analysis, Person's Chisquare test and Fischer's exact test.
RESULTS: The prevalence of food insecurity was more significant than the prevalence of food secured, at 55.4% and 44.6% respectively. The stunting among the children rated at 34.8%, followed by 7.2% of the sample found underweight, 7.8% (BAZ) and 16.1% (BAZ) of them were wasted, and overweight & obese, proportionately. This study discovered that household size was the sole determinant of household food security status. This finding suggested that size of a household influenced the odds of a household being food insecure.
CONCLUSION: The findings of this study provide insights into how the COVID-19 pandemic have an impact on children's nutritional status especially those from low-income and bigger size households. Therefore, more thorough and effective interventions should be designed particularly targeting this urban poor community to enhance their nutritional status and health.
Gelatin controversies in food, pharmaceuticals, and personal care products: Authentication methods, current status, and future challenges

Ali E, Sultana S, Hamid SBA, Hossain M, Yehya WA, Kader A, et al.

Crit Rev Food Sci Nutr, 2018 Jun 13;58(9):1495-1511.
PMID: 28033035 DOI: 10.1080/10408398.2016.1264361

Gelatin is a highly purified animal protein of pig, cow, and fish origins and is extensively used in food, pharmaceuticals, and personal care products. However, the acceptability of gelatin products greatly depends on the animal sources of the gelatin. Porcine and bovine gelatins have attractive features but limited acceptance because of religious prohibitions and potential zoonotic threats, whereas fish gelatin is welcomed in all religions and cultures. Thus, source authentication is a must for gelatin products but it is greatly challenging due to the breakdown of both protein and DNA biomarkers in processed gelatins. Therefore, several methods have been proposed for gelatin identification, but a comprehensive and systematic document that includes all of the techniques does not exist. This up-to-date review addresses this research gap and presents, in an accessible format, the major gelatin source authentication techniques, which are primarily nucleic acid and protein based. Instead of presenting these methods in paragraph form which needs much attention in reading, the major methods are schematically depicted, and their comparative features are tabulated. Future technologies are forecasted, and challenges are outlined. Overall, this review paper has the merit to serve as a reference guide for the production and application of gelatin in academia and industry and will act as a platform for the development of improved methods for gelatin authentication.
Fulltext Hospital Food Service Strategies to Improve Food Intakes among Inpatients: A Systematic Review

Osman NS, Md Nor N, Md Sharif MS, Hamid SBA, Rahamat S

Nutrients, 2021 Oct 18;13(10).
PMID: 34684649 DOI: 10.3390/nu13103649

This review aims to identify hospital food service strategies to improve food consumption among hospitalized patients. A systematic search that met the inclusion and exclusion criteria was manually conducted through Web of Science and Scopus by an author, and the ambiguities were clarified by two senior authors. The quality assessment was separately conducted by two authors, and the ambiguities were clarified with all the involved authors. Qualitative synthesis was used to analyze and summarized the findings. A total of 2432 articles were identified by searching the databases, and 36 studies were included. The majority of the studies applied menu modifications and meal composition interventions (n = 12, 33.3%), or included the implementation of the new food service system (n = 8, 22.2%), protected mealtimes, mealtime assistance and environmental intervention (n = 7, 19.4%), and attractive meal presentation (n = 3, 8.3%). Previous studies that used multidisciplinary approaches reported a significant improvement in food intake, nutritional status, patient satisfaction and quality of life (n = 6, 16.7%). In conclusion, it is suggested that healthcare institutions consider applying one or more of the listed intervention strategies to enhance their foodservice operation in the future.
Fulltext Optimization of the Synthesis of Superhydrophobic Carbon Nanomaterials by Chemical Vapor Deposition

Aljumaily MM, Alsaadi MA, Das R, Hamid SBA, Hashim NA, AlOmar MK, et al.

Sci Rep, 2018 02 09;8(1):2778.
PMID: 29426860 DOI: 10.1038/s41598-018-21051-3

Demand is increasing for superhydrophobic materials in many applications, such as membrane distillation, separation and special coating technologies. In this study, we report a chemical vapor deposition (CVD) process to fabricate superhydrophobic carbon nanomaterials (CNM) on nickel (Ni)-doped powder activated carbon (PAC). The reaction temperature, reaction time and H2/C2H2 gas ratio were optimized to achieve the optimum contact angle (CA) and carbon yield (CY). For the highest CY (380%) and CA (177°), the optimal reaction temperatures were 702 °C and 687 °C, respectively. However, both the reaction time (40 min) and gas ratio (1.0) were found to have similar effects on CY and CA. Based on the Field emission scanning electron microscopy and transmission electron microscopy images, the CNM could be categorized into two main groups: a) carbon spheres (CS) free carbon nanofibers (CNFs) and b) CS mixed with CNFs, which were formed at 650 and 750 °C, respectively. Raman spectroscopy and thermogravimetric analysis also support this finding. The hydrophobicity of the CNM, expressed by the CA, follows the trend of CS-mixed CNFs (CA: 177°) > CS-free CNFs (CA: 167°) > PAC/Ni (CA: 65°). This paves the way for future applications of synthesized CNM to fabricate water-repellent industrial-grade technologies.

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