Hasil untuk "Chemical technology"

J. Lunsford

J. Millstone, Sarah J. Hurst, G. S. Métraux et al.

Chunping Xu, R. Arancon, J. Labidi et al.

N. Sozer, J. Kokini

S. P. Dharupaneedi, S. Nataraj, M. Nadagouda et al.

The potential emerging pollutants (PEPs) such as hazardous chemicals, toxic metals, bio-wastes, etc., pose a severe threat to human health, hygiene and ecology by way of polluting the environment and water sources. The PEPs are originated from various industrial effluent discharges including pharmaceutical, food and metal processing industries. These PEPs in contact with water may pollute the water and disturb the aquatic life. Innumerable methods have been used for the treatment of effluents and separating the toxic chemicals/metals. Of these methods, membrane-based separation processes (MBSPs) are effective over the conventional techniques for providing clean water from wastewater streams at an affordable cost with minimum energy requirement. Microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), and forward osmosis (FO) methods as well as hybrid technologies are discussed citing the published results of the past decade.

A. Atkinson, Onur G. Apul, O. Schneider et al.

Since first hypothesizing the existence of nanobubbles (NBs) in 1994, the empirical study of NB properties and commercialization of NB generators have rapidly evolved. NBs are stable spherical packages of gas within liquid and are operationally defined as having diameters less than 1000 nm, though they are typically in the range of 100 nm in one dimension. While theories still lack the ability to explain empirical evidence for formation of stable NBs in water, numerous NB applications have emerged in different fields, including water and wastewater purification where NBs offer the potential to replace or improve efficiency of current treatment processes. The United Nations identifies access to safe drinking water as a human right, and municipal and industrial wastewaters require purification before they enter water bodies. These protections require treatment technologies to remove naturally occurring (e.g., arsenic, chromium, fluoride, manganese, radionuclides, salts, selenium, natural organic matter, algal toxins), or anthropogenic (e.g., nitrate, phosphate, solvents, fuel additives, pharmaceuticals) chemicals and particles (e.g., virus, bacteria, oocysts, clays) that cause toxicity or aesthetic problems to make rivers, lakes, seawater, groundwater, or wastewater suitable for beneficial use or reuse in complex and evolving urban and rural water systems. NBs raise opportunities to improve current or enable new technologies for producing fewer byproducts and achieving safer water. This account explores the potential to exploit the unique properties of NBs for improving water treatment by answering key questions and proposing research opportunities regarding (1) observational versus theoretical existence of NBs, (2) ability of NBs to improve gas transfer into water or influence gas trapped on particle surfaces, (3) ability to produce quasi-stable reactive oxygen species (ROS) on the surface of NBs to oxidize pollutants and pathogens in water, (4) ability to improve particle aggregation through intraparticle NB bridging, and (5) ability to mitigate fouling on surfaces. We conclude with key insights and knowledge gaps requiring research to advance the use of NBs for water purification. Among the highest priorities is to develop techniques that measure NB size and surface properties in complex drinking and wastewater chemistries, which contain salts, organics, and a wide variety of inorganic and organic colloids. In the authors' opinion, ROS production by NB may hold the greatest promise for usage in water treatment because it allows movement away from chemical-based oxidants (chlorine, ozone) that are costly, dangerous to handle, and produce harmful byproducts while helping achieve important treatment goals (e.g., destruction of organic pollutants, pathogens, biofilms). Because of the low chemical requirements to form NBs, NB technologies could be distributed throughout rapidly changing and increasingly decentralized water treatment systems in both developed and developing countries.

S. Wong, Riyang Shu, Jiaguang Zhang et al.

Despite the enormous research efforts in recent years regarding lignin depolymerisation and functionalisation, few commercial products are available. This review provides a summary and viewpoint of extensive research in the lignin-to-product valorisation chain, with an emphasis on downstream processing of lignin derived feedstock into end products. It starts with an introduction of available platform chemicals and polymeric derivatives generated from lignin via existing depolymerisation and functionalisation technologies. Following that, detailed analyses of various strategies for the downstream processing of lignin derived platform chemicals and materials into fuels, valued-added chemicals and functional polymers are provided. A concise techno-economic analysis of various downstream processes is conducted based on the market demand of the end product, economic potential and technological readiness, enabling the identification of processes that are potentially both economically competitive and commercially feasible, and shedding light on processes which deserve further technological development. We wish this review will stimulate further advances in the sustainable production of value-added products from lignin to integrate this invaluable "bio-waste" into the chemical/materials supply chain.

Charles H. Camp Jr, M. Cicerone

Marina Cvjetko Bubalo, S. Vidovic, I. R. Redovniković et al.

In many industrial processes, large quantities of volatile and flammable organic solvents are used in various reaction systems and separation steps defining a major part of the environmental and economic performance of a process. Accordingly, a growing area of research in the development of green technologies is devoted to designing new, environment-friendly and tunable solvents the use of which would meet both technological and economic demands. Among proposed solvents, room temperature ionic liquids, supercritical and subcritical fluids and solvents from natural and renewable sources stand out as the most promising approaches for current solvent innovation. A brief overview of up-to-date knowledge regarding these solvents is presented herein, with special emphasis on their properties, applications and further perspectives as truly green industrial solvents. © 2015 Society of Chemical Industry

Spyridoula G. Farmaki, Dimitrios A. Exarchos, Vasileios Dracopoulos et al.

Recent advances in nanotechnology have highlighted the transformative potential of carbon-based nanomaterials, such as carbon nanofibers, carbon nanotubes, and graphene, in cementitious systems. These materials have shown a remarkable ability to enhance the mechanical strength, fracture toughness, and overall functional performance of cementitious composites. Their nanoscale dimensions and exceptional intrinsic properties allow for effective stress bridging, crack arrest, and matrix densification. Despite these promising features, the current understanding remains limited, particularly regarding their application to concrete. Furthermore, literature lacks systematic, parallel evaluations of their respective effectiveness in improving both mechanical performance and long-term durability, as well as their potential to impart true multifunctionality to concrete structures. It is worth noting that significant and statistically significant improvements in fracture behavior were observed at specific nanofiller concentrations, suggesting strong potential for the material system in next-generation innovative infrastructure applications. Experimental results demonstrated that both CNTs and GNPs significantly enhanced the mechanical performance of concrete, with flexural strength increases of approximately 49% and 38%, and compressive strength improvements of 22% and 47%, respectively, at optimum contents of 0.6 wt.% CNTs and 0.8 wt.% GNPs. SEM analyses confirmed improved matrix densification and interfacial bonding at these concentrations, while higher dosages led to agglomeration and reduced performance. This gap highlights the need for targeted experimental studies to elucidate the structure-property relationships governing these advanced materials.

A. Studart

C. B. Rosen, M. Francis

Islam Sayah, Ibtissem Chakroun, Claudio Gervasi et al.

Bacterial nanocellulose (BNC) has gained considerable interest over the last decade due to its unique properties and versatile applications. However, the low yield and the high production cost significantly limit its industrial scalability. The proposed study explores the isolation of new BNC producers from date palm sap and the use of date waste extract as a sustainable carbon source to improve BNC productivity. Results revealed three potential BNC producers identified as <i>Komagataeibacter</i> sp. IS20, <i>Komagataeibacter</i> sp. IS21, and <i>Komagataeibacter</i> sp. IS22 with production yield of 1.7 g/L, 0.8 g/L and 1.8 g/L, respectively, in Hestrin-Schramm (HS) medium. The biopolymer characterization indicated the presence of type I cellulose, a high thermal stability, and a highly dense network made of cellulose nanofibrils for all BNC samples. The isolate IS22, showing the highest productivity, was selected for an optimization procedure using a full factorial design with date waste extract as a carbon source. The BNC yield increased to 6.59 g/L using 4% date waste extract and 2% ethanol after 10 days of incubation compared to the standard media (1.8 g/L). Two probiotic strains, including <i>Bacillus subtilis</i> (BS), and <i>Lactobacillus plantarum</i> (LP) were successfully encapsulated into BNC matrix through a co-culture approach. The BNC-LP and BNC-BS composites showed antibacterial activity against <i>Pseudomonas aeruginosa</i>. BNC–probiotic composites have emerged as a promising strategy for the effective delivery of viable probiotics in a wide range of applications. Overall, this study supports the use of date waste extract as a sustainable carbon source to enhance BNC productivity and reduce the environmental footprint using a high-yielding producer (IS22). Furthermore, the produced BNC demonstrated promising potential as an efficient carrier matrix for probiotic delivery.

Hao Jin, Jiandong Ding, Xiaoguo Zhang et al.

Abstract Modulating the balance between pro- and anti-inflammatory monocyte subsets holds therapeutic promise in acute myocardial infarction (AMI); however, effective and selective strategies are still lacking. In this study, we are the first to identify Ten-Eleven-Translocation 3 (TET3) expression in circulating monocytes as an independent predictor of AMI occurrence and patient prognosis in a clinical cohort. Building on this novel insight, we engineered a monocyte-targeted RNAi delivery system designed to silence TET3 expression selectively. The platform employs periodic mesoporous silica nanoparticles (PMS) loaded with siTET3, and is surface-modified with polyethylenimine (PEI) and polyethylene glycol (PEG) to enhance cellular uptake. Critically, we further functionalized the system with a CD14 receptor-recognizing transmembrane peptide (Cys-Gly-Trp-Arg-Arg-Arg-NH₂), enabling precise monocyte targeting and internalization. Our targeted nanotherapeutic successfully reprogrammed inflammatory monocytes in vitro, leading to attenuated pro-inflammatory phenotypes. In vivo, treatment with siTET3-loaded nanoparticles markedly reduced infarct size and myocardial fibrosis in murine AMI models. Importantly, translational validation in a porcine AMI model demonstrated substantial suppression of cardiac inflammation and improved post-infarction outcomes following systemic administration of the nanotherapeutic. Graphical abstract

Syahidah N. Zulkifli, H. A. Rahim, W. Lau

Water monitoring technologies are widely used for contaminants detection in wide variety of water ecology applications such as water treatment plant and water distribution system. A tremendous amount of research has been conducted over the past decades to develop robust and efficient techniques of contaminants detection with minimum operating cost and energy. Recent developments in spectroscopic techniques and biosensor approach have improved the detection sensitivities, quantitatively and qualitatively. The availability of in-situ measurements and multiple detection analyses has expanded the water monitoring applications in various advanced techniques including successful establishment in hand-held sensing devices which improves portability in real-time basis for the detection of contaminant, such as microorganisms, pesticides, heavy metal ions, inorganic and organic components. This paper intends to review the developments in water quality monitoring technologies for the detection of biological and chemical contaminants in accordance with instrumental limitations. Particularly, this review focuses on the most recently developed techniques for water contaminant detection applications. Several recommendations and prospective views on the developments in water quality assessments will also be included.

Martin Krallinger, O. Rabal, A. Lourenço et al.

Chaoli Zeng, Guangqing Xia, Xing Zhong et al.

Evaluating the stray light cancellation performance of an optical system is an essential step in the search for superior optical systems. However, the existing evaluation methods, such as the Monte Carlo method and the ray tracing method, suffer from the problems of vast arithmetic and cumbersome processes. In this paper, a method for a rapid stray light performance evaluation model and quantitatively determining high-magnitude stray light outside the field of view are proposed by adopting the radiative transfer theory based on the scattering property of the bidirectional scattering distribution function (BSDF). Under the global coordinates, based on the derivation of the light vector variation relationship in the near-linear system, the specific structural properties of the off-axis reflective optical system, and the specular scattering properties, a fast quantitative evaluation model of the optical system’s stray light elimination capability is constructed. A loop nesting procedure was designed based on this model, and its validity was verified by an off-axis reflective optical system. It successfully fitted the point source transmittance (PST) curve in the range of specular radiation reception angles and quantitatively predicted the prominence due to incident stray light outside the field of view. This method does not require multiple software to work in concert and requires only 10^–5 orders of magnitude of computing time, which is suitable for the rapid stray light assessment and structural screening of off-axis reflective optical systems with a good symmetry. The method is promising for improving imaging radiation accuracy and developing lightweight space cameras with low stray light effects.

Applied Bionics and Biomechanics

P. Blau, Joseph R. Davis

Krishanthi C. Weerasinghe, Tianyang Wang, Junpeng Zhuang et al.

Engineering organic small molecule materials capable of generating Wannier excitons is a pinnacle of research for organic optoelectronic devices. In this work, we used a coherently degenerate state strategy to design and synthesize an organic small molecule dimer compound consisting of two triphenylamine based monomers. A technique was developed to identify the coherently degenerate states in the dimer compound from the results of density functional theory calculations of. The time-resolved fluorescence measurements showed that the lifetime of the Wannier excitons in the newly designed dimer compound is less solvent dependent than that of the Frenkel excitons in the monomer. The power conversion efficiency of the photovoltaics constructed using this new material increases by 8-fold in comparison to that using the monomer. The method developed here offers extraordinary opportunities for rational design of organic materials to generate Wannier excitons.