Magnetophoresis Of Poly (SODIUM 4-STYRENESULFONATE) Fe3O4 Clusters The Influence of Colloidal Stability

Kajian ini didedikasikan untuk mendedahkan pengaruh kestabilan berkoloid terhadap magnetoforesis zarah-zarah Fe3O4. Pertama sekali, kestabilan berkoloid Fe3O4 terdedah telah berjaya dipertingkatkan selepas permukaanya disalut dengan polimer anionik yang kuat, poli(natrium 4-stirenasulfonat) berberat molekul 70K Da (PSS 70K), melalui teknik pascasalutan diaruh oleh elektrostatik yang dilakukan pada pH ~ 3.50. Peningkatan kestabilan berkoloid yang dicapai oleh kelompok-kelompok PSS 70K/Fe3O4 tersebut sebahagian besarnya disumbangkan daripada tolakan elektrostatik dan tolakan sterik yang masing-masingnya mengatasi tarikan dwikutubdwikutub magnet apabila jarak antara zarah adalah < 97 nm dan < 50 nm. Namun begitu, kajian permisahan magnet menunjukkan bahawa semakin stabil berkoloid Fe3O4 itu, semakin sukar untuk memisahkannya dengan magnet. Dengan mengesani profil magnetoforesis bawah kecerunan medan magnet dengan purata magnitud 40.55 T/m, didapati bahawa Fe3O4 terdedah mencapai 100 % permisahan dalam masa 8 minit; manakala kelompok-kelompok PSS 70K/ Fe3O4 tidak dapat dipisahkan sepenuhya walaupun masa bagi permisahan magnet tersebut dilanjutkan sehingga satu jam. Dalam erti kata yang lain, salutan polimer yang pada mulanya digunakan untuk menstabilkan Fe3O4 itu secara elektrosterik justerunya menjejaskan kebersambutan mereka terhadap magnet. Berlainan daripada Fe3O4 terdedah yang menjalani magnetoforesis secara berkerjasama, didapati bahawa kelompok-kelompok PSS 70K/Fe3O4 mengalami magnetoforesis berdasarkan pemeringkatan mengikut saiz di mana pemisahan magnetnya dikawal oleh kehadiran taburan saiz hidrodinamik di dalam ampaian tersebut. Selain daripada itu, kajian mikroskopik seterusnya mendedahkan perbezaan di antara kedua-dua entiti di mana kelompok-kelompok PSS 70K/Fe3O4 cenderung untuk terhala sesama sendiri menjadi struktur seperti benang; manakala Fe3O4 terdedah cenderung untuk agregat sesama sendiri menjadi struktur fraktal yang berpelbagai dimensi. Pendekatan perhimpunan pengantara elektrostatik yang mudah telah dicadangkan dalam kajian ini untuk menghasilkan kelompokkelompok PSS 70K/Fe3O4 yang berpelbagai saiz (~ 200 nm hingga ~ 700 nm ). Di sini, didapati bahawa kelompok-kelompok PSS 70K/Fe3O4 dengan purata saiz kelompok 459 nm bukan sahaja mempunyai kestabilan berkoloid yang baik, malahan menawarkan kebolehpisahan magnet yang tinggi (> 98 % kecekapan pemisahan dicapai apabila didedahkan kepada kecerunan medan magnet yang sama untuk 5 minit sahaja). Penemuan ini menunjukkan bahawa memanipulasi saiz kelompok bagi kelompok-kelompok PSS 70K/Fe3O4 boleh digunakan sebagai penyelesaian untuk kebimbangan keseimbangan antara peningkatan kestabilan berkoloid dan kebolehpisahan magnet. Dalam bahagian akhir kajian ini, kestabilan berkoloid bagi kelompok-kelompok PSS 70K/Fe3O4 didapati telah merosot selepas penambahan ionion logam (e.g., Ag+, Cu2+, Cr3+, Ca2+, Mg2+). Keputusan menunjukkan bahawa kepekatan kation logam memainkan peranan yang lebih penting daripada kekuatan ion yang lazimnya dipercayai dalam meningkatkan proses pengagregatan tersebut. Di samping itu, dengan kehadiran ion Cu2+, bahan-bahan organic terlarut seperti asid humik dan natrium alginat didapati membentuk kompleks dengan kelompokkelompok PSS 70K/Fe3O4. Pembentukan kompleks ini kemudiannya juga akan mempengaruhi kestabilan berkoloid dan justerusnya kelakuan magnetoforesis kelompok-kelompok PSS 70K/Fe3O4. ________________________________________________________________________________________________________________________ The present work is dedicated to reveal the influence of colloidal stability towards magnetophoresis of Fe3O4 particles. First of all, colloidal stability of bare Fe3O4 was successfully enhanced after surface coating with a strong anionic polymer, poly(sodium 4-styrenesulfonate) of molecular weight 70K Da (PSS 70K), through electrostatic-induced post-coating technique conducted at pH ~3.50. Enhanced colloidal stability attained by the resultant PSS 70K/Fe3O4 clusters is mainly contributed from the electrostatic and the steric repulsion, which overwhelm the magnetic dipole-dipole attraction, when the interparticle distance is < 97 nm and < 50 nm, respectively. However, magnetic separation study showed that the more colloidally stable the Fe3O4 is, the harder it is to be magnetically separated. By carefully tracking on the magnetophoresis profiles under magnetic field gradient of average magnitude 40.55 T/m, it was found that bare Fe3O4 attained ~ 100 % separation within 8 minutes; while there was no complete separation for PSS 70K/Fe3O4 clusters even the magnetic separation time was extended to 1 hour. In another words, the polymer coating that was initially employed to electrosterically stabilize the Fe3O4 in turn compromises their magnetic responsiveness. Unlike the bare Fe3O4 which undergo a typical cooperative magnetophoresis, it was found that the PSS 70K/Fe3O4 clusters experienced a size-fractionation based magnetophoresis in which the magnetic separation was controlled by the presence of distribution of hydrodynamic sizes in the suspension. Besides that, microscopic study further revealed the differences between both entities in which PSS 70K/Fe3O4 clusters tend to self-oriented into thread-like structures; while bare Fe3O4 tend to self-aggregate into fractal structures of various dimensions. A simple electrostatic-mediated assembly approach was proposed in this study to produce PSS 70K/Fe3O4 clusters of various sizes (~200 nm up to ~ 700 nm). Here, it was found that PSS 70K/Fe3O4 clusters of average cluster size 459 nm not only possess good colloidal stability, but also offer high magnetic separability (> 98 % separation efficiency was attained when exposed to the same magnetic field gradient for just 5 minutes). This finding indicates that manipulating the cluster sizes of the PSS 70K/Fe3O4 clusters can be used as the solution for the trade-off concern between enhanced colloidal stability and magnetic separability. In the last part of this study, it was revealed that the colloidal stability of PSS 70K/Fe3O4 clusters being deteriorated after addition of metal ions (e.g., Ag+, Cu2+, Cr3+, Ca2+, Mg2+). Results showed that it is the concentration of the metal cation, instead of the conventionally believed ionic strength, plays a more decisive role in enhancing the aggregation process. In addition, with the presence of Cu2+ ion, dissolve organic matters such as humic acid and sodium alginate was found to form complexes with the PSS 70K/Fe3O4 clusters. This formation of complexes can later on influence the colloidal stability and thus magnetophoresis behavior of the PSS 70K/Fe3O4 clusters

Unlocking Nanotechnology Adoption Intention in the Malaysian Food Industry

The purpose of this study is to investigate the factors that motivate nanotechnology adoption in the food industry. The study collects 101 responses from food industry operators in Klang Valley, Malaysia, via a quantitative field survey. The data was analysed using Structural Equation Modelling (SEM). The findings show that effort expectation, price value, and trust have no statistical impact on nanotechnology adoption, whereas performance expectancy and top management support have positive effects. Given that this study is one of the few that investigates factors influencing nanotechnology adoption, it should give useful information for future studies on the food industry and nanotechnology adoption among researchers and practitioners

Upskilling and reskilling requirement in logistics and supply chain industry for the fourth industrial revolution

For years, the logistics and supply chain industries have been optimized to reduce cost, minimize the carried inventories and increase the efficiency of assets utilization. Besides that, the impact of industrial revolution 4.0 (IR 4.0) has queried for more new skills for a more demanding job scope. In particular, many traditional operation methods have been gradually replaced by automation-based operation. Hence the requirement for upskilling and reskilling became appealing. The present paper discusses the role of upskilling and reskilling during IR 4.0, a method to implement upskilling and reskilling training, the role of the Human Resource Development Fund (HRDF), as well as the challenges faced during the implementation of reskilling and upskilling in the logistics industries. Methods: Inductive reasoning is employed in the paper, which is backed up by a study of related scholarly journal papers to uncover the Malaysian upskilling and reskilling requirement in the logistics industry during IR 4.0from both intrinsic and extrinsic lenses. Results: The paper claims that changing the workplace and workforce, increase employees competitiveness and costeffectiveness in long term is the main importance of upskilling and reskilling. Nevertheless, firms cannot disregard the needs for technical and human skills as well as the HRDF initiatives. These include the creation of a digital culture with the right training and development to uphold the local experts. Conclusions: Despite the paper's qualitative approach, the findings will provide a clearer understanding of the upskilling and reskilling requirements for IR 4.0, as well as a foundation for future study. This paper proposes an alternative strategy to diversify the economy and enter IR 4.0 for a developing country that is dependent on a non-renewable source

Amine-based solvent for CO2 absorption and its impact on carbon steel corrosion: A perspective review

Carbon dioxide (CO2) is one of the commonly emitted gaseous by-products in industrial processes. While CO2 gas is the main cause to greenhouse effect, various CO2 capture technologies have been proposed and implemented to sequester the CO2 before the waste gases being released into the atmosphere. One of the mature technologies for CO2 absorption is by using amine-based solvents. In this regard, different single amine solvents or blended amine solvents have been proven for their capability to remove CO2. However, the dissolution and reaction of CO2 gas with the amine solvents turn the solution corrosive. Such phenomenon is undesired as it posts corrosion problem to the absorption column, which normally built of carbon steel material. Henceforth, understanding the behaviour of different amine-based solvents in absorbing CO2 and its subsequent impact on carbon steel corrosion is very significant. In this review article, we will outline some of the more commonly used solvents and their respective advantages and disadvantages, motivating further investigation into the corrosion tendency. Meanwhile, existing gaps in this research area are discussed for future investigation

Simulation of magnetic field gradient from Working principle and application of magnetic separation for biomedical diagnostic at high and low field gradient

Magnetic separation is a versatile technique used in sample preparation for diagnostic purpose. For such application, an external magnetic field is applied to drive the separation of target entity (e.g. bacteria, viruses, parasites, cancer cells) from a complex raw sample in order to ease the subsequent task(s) for disease diagnosis. This separation process not only can be achieved via the utilization of high magnetic field gradient, in most cases, low magnetic field gradient with magnitude less than 100 T m⁻¹ is equally feasible. It is the aim of this review paper to summarise the usage of both high gradient magnetic separation (HGMS) and low gradient magnetic separation (LGMS) techniques in this area of research. It is noteworthy that effectiveness of the magnetic separation process not only determine the outcome of a diagnosis but also directly influence its accuracy as well as sensing time involved. Therefore, understanding the factors that simultaneously influence the efficiency of both magnetic separation process and target detection is necessary. Moreover, for LGMS, there are several important considerations that should be taken into account in order to ensure its successful implementation. Hence, this review paper aims to provide an overview to relate all this crucial information by linking the magnetic separation theory to biomedical diagnostic applications

Impact of solute properties and water matrix on nanofiltration of pesticides

The application of different nanofiltration membranes for the separation of pesticides, i.e., atrazine and dimethoate, from aqueous solutions is described. The nanoflitration membranes DK, NF270, NF200, and NF90 were tested for the pesticide retention performance in a stirred dead-end filtration system. NF90 demonstrated the best pesticide retention with over 95 % for atrazine and approximately 80 % for dimethoate. All membranes consistently showed better retention of atrazine than of dimethoate. Dissolving the pesticides in river or tap water amplified the overall pesticide retention performance, indicating that filtration in water treatment plants could render superior pesticide retention. However, a lower flux was obtained for the filtration of tap and river water