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Liquid phase microextraction is a state-of-the-art micro-analytical work with numerous advantages documented in the scientific literature. One of the most intriguing subclasses is the CO.sub.2-effervescence assisted dispersive liquid-liquid microextraction method. Working theory was based on an acid-based reaction involving a proton donor and a carbon dioxide source. The paper outlines the considerations regarding the microextraction performance that can change in terms of physical, chemical properties, and its application for environmental sample analysis. A wide range of the developed and applied novel methods clearly indicates that CO.sub.2-effervescence is still in demand among researchers looking for new achievements in green analytical chemistry. This review focuses on the method application for the extraction and preconcentration of different classes of micropollutants (organic or inorganic) in environmental waters. New breakthroughs in the microextraction process show enhanced performance of the system in terms of sensitivity, accuracy, precision and the attempt to reduce extraction steps during separation or retrieval processes for low concentrations of analytes. Future direction refers to the improvement of green parameters in the microextraction, use of extracting agents as co-dispersers (solid or liquid), removal of elution dependency in solvents by the use of super-paramagnetic properties, etc. The success stories of the method development are widely documented in the literature. This microextraction technique will continue to serve as a reliable tool for the determination of micropollutants in environmental samples., Author(s): Sarveishwhary Rajendran [sup.1], Saw Hong Loh [sup.1], Marinah Mohd Ariffin [sup.1], Wan Mohd Afiq Wan Mohd Khalik [sup.1] Author Affiliations: (1) grid.412255.5, 0000 0000 9284 9319, Faculty of Science [...]

Clean water quality is dependent on the absence or complete removal of polar ionic micropollutant molecules and their associated products from the water. Utilizing copper Isonicotinate metal–organic frameworks ([Cu (INA)-MOF) a modified copper-based magnetic composite metal–organic framework ([Cu (INA)2]-MOF@Fe3O4) is mechanically synthesized under environmentally friendly conditions, and an adsorptive removal of salbutamol in water was successfully achieved in both synthesized materials. Characterization toward the materials has been carried out using X-ray diffraction, Brunauer–Emmett–Teller, field emission scanning microscopy, scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Our synthesized ([Cu (INA)2]-MOF@Fe3O4 used as an adsorbent in water showed enhanced performance in the removal of the model salbutamol within a shorter contact time (40 min) with the pseudo-second-order and Langmuir models providing the most accurate statistical descriptions of the process's kinetics and isotherms, respectively, while thermodynamic studies indicated that the process was endothermic, spontaneous, and the material demonstrated very good reusability and regeneration with a very good percentage recovery even after the fifth cycle. [ABSTRACT FROM AUTHOR]

β-agonists are a class of synthetic phenylethanolamine compounds that were originally designed to reduce asthma and chronic obstructive pulmonary disease. They remain widely used but unfortunately, misuse in animal farming and sports activities due to their huge medical and economic benefits. As a result, they have been found in a variety of matrices and subsequently end up in multiple water bodies in the environment. However, their environmental occurrence and fates are only evaluated on an occasional basis as they happen at a very trace level. The development of appropriate analytical procedures is critical in providing reliable data related to their occurrence and concentrations in various water bodies. Coupling high-performance liquid chromatography and mass spectrometry have been the most extensively used approach for great sensitivity and high selectivity for their determination in the environment. Sample preparation is important for obtaining lower detection limits, and the online solid-phase extraction has been comprehensively used considering the physicochemical properties of β-agonists. This review presented the systematic development of the preceding research on β-agonist detection approaches published between 1985-2020, emphasizing their analysis, resolution in environmental waters, and highlighting the significant scientific approach from the existing analytical techniques suitable for their ultra-trace determination. [ABSTRACT FROM AUTHOR]

Liquid phase microextraction is a state-of-the-art micro-analytical work with numerous advantages documented in the scientific literature. One of the most intriguing subclasses is the CO2-effervescence assisted dispersive liquid−liquid microextraction method. Working theory was based on an acid-based reaction involving a proton donor and a carbon dioxide source. The paper outlines the considerations regarding the microextraction performance that can change in terms of physical, chemical properties, and its application for environmental sample analysis. A wide range of the developed and applied novel methods clearly indicates that CO2-effervescence is still in demand among researchers looking for new achievements in green analytical chemistry. This review focuses on the method application for the extraction and preconcentration of different classes of micropollutants (organic or inorganic) in environmental waters. New breakthroughs in the microextraction process show enhanced performance of the system in terms of sensitivity, accuracy, precision and the attempt to reduce extraction steps during separation or retrieval processes for low concentrations of analytes. Future direction refers to the improvement of green parameters in the microextraction, use of extracting agents as co-dispersers (solid or liquid), removal of elution dependency in solvents by the use of super-paramagnetic properties, etc. The success stories of the method development are widely documented in the literature. This microextraction technique will continue to serve as a reliable tool for the determination of micropollutants in environmental samples. [ABSTRACT FROM AUTHOR]

The potential use of agriculture and marine biowaste to produce an adsorbent for the removal of heavy metals from wastewater was studied. A bio-adsorbent was produced from the combination of rice straws and bulk seashells via self-assembled precipitation method. The chitosan:hydroxyapatite ratio in coating rice straw was set at 1:1. The molarity of the stabilizer (sodium hydroxide) was manipulated to determine the highest adsorption capacity of selected heavy metals and its effect on the physical and chemical properties of the prepared adsorbents. Isotherm tests showed that the equilibrium sorption data were better represented by the Langmuir model. The optimum bio-adsorbent (25-CH/HAP/RSA1.5M) was composed of 25% weight combination of chitosan:hydroxyapatite and stabilizer solution with a molarity of 1.5 mol L–1 showed the highest adsorption of heavy metal ions and was selected for subsequent study. Lead(II) (75.19) had the highest adsorption capacity of heavy metal (qmax), followed by zinc(II) (47.39), manganese(II) (22.73), iron(III) (19.23), nickel(II) (15.02), and copper(II) (10.72). Therefore, this study highlights the potential of an adsorbent derived from rice straw and seashells as a cost-effective alternative for heavy metal removal. [ABSTRACT FROM AUTHOR]

BACKGROUND: Membrane fouling in downstream processing has become a major obstacle in enzyme production. The use of a membrane with high surface hydrophilicity may be an acceptable way to overcome this problem. In this study, the effects of dip time on chitosan incorporation were investigated to produce a low fouling ultrafiltration membrane for trypsin separation. RESULT: Pristine ultrafiltration membrane with a polymer concentration of 15% was developed via phase inversion. Membrane surface modification was performed using chitosan solution with different dip times. Membranes with a 60-min dip time provided optimum trypsin transmission (about 91.8%). Such membranes have a high permeability coefficient (71 L m−2 h−1) and good porosity (about 89.6%). The hydrophilicity of this modified membrane was also improved by 50% compared with the native membrane, and its flux recovery was about 89.8%. The successful assembly of chitosan onto the membrane's surface was ascertained by ATR-FTIR and X-ray diffractometry (XRD). The morphology of this membrane was significantly different from that of native membrane. CONCLUSION: The experimental results show that membrane dip time exerts a significant influence on the self-assembly of chitosan particles onto the membrane's surface, and this process can be used to produce a potentially low-fouling UF membrane for trypsin separation. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]