Utilization of ionic liquid for ICP-OES based trace metal assay in thorium matrix for decrease in liquid organic waste, cost, human exposure and time of analysis

Ionic liquid based 'Green" separation methodology was used for drastic reduction in organic phase requirement, generation of organic liquid waste, time of analysis, personal exposure towards radiotoxic environment, less chances...

Recycling of Spent Reverse Osmosis Membranes for Second Use in the Clarification of Wet-Process Phosphoric Acid

Various techniques have been used to “clean-up” wet-process phosphoric acid such as precipitation, flotation and adsorption. To address the potential of membrane processes in the phosphoric acid clarification process, this study explores the benefits of membrane techniques as a green separation technique for phosphoric acid clarification in an eco-efficient way through the use of recycling spent reverse osmosis membrane. Regenerated membrane was used to study the phosphoric acid clarification at a laboratory scale. They were immersed in an oxidizer for at most seven days. The samples were characterized systematically before immersion in an oxidant media. In this study, the potential to regenerate spent membranes and application of this media to clarify the 29% P2O5 phosphoric acid was demonstrated. This study shows, through experiments, that the reverse osmosis (RO) membranes could achieve a rejection of 70% and 61% for suspended solid and organic matter, respectively. These promising results will pave the way for implementation of these membranes in phosphoric acid treatment. Moreover, besides being economically advantageous, the use of the spent membrane is likely an environmentally friendly route (no waste, no organic solvent and effluent to be regenerated later on).

Novel utilisation of ultrawide-field fundus photography for detecting retinal nerve fibre layer defects in glaucomatous eyes

Background/aimsEvaluation of the retinal nerve fibre layer (RNFL) is important for identifying glaucomatous damage. Ultrawide-field fundus photography (UWP) imaging is increasingly used in the ophthalmological field; however, it is unknown whether it can be used for detecting RNFL defects (RNFLDs). We investigated whether RNFLD can be detected with UWP images and compared the clinical effectiveness of three types of images for detecting RNFLD: conventional red-free RNFL photography (RFP), non-mydriatic UWP and digitally converted green separation of non-mydriatic UWP (G-UWP).MethodsEyes with glaucoma or glaucoma suspect and normal control eyes meeting the eligibility criteria were consecutively enrolled from September 2019 to April 2020. Their conventional RFP, non-mydriatic UWP and G-UWP images were assessed for detecting RNFLD to evaluate the sensitivity and specificity for detecting RNFLD.ResultsThree image sets of 196 participants (84 normal control, 25 glaucoma suspect and 87 glaucoma) were obtained. The sensitivity of G-UWP (94.6%; 95% CI 88.7 to 98.0) and RFP (92.9%; 95% CI 86.4 to 96.9) was higher than that of UWP (82.1%; 95% CI 73.8 to 88.7; p<0.05). The sensitivities of G-UWP and RFP are comparable. The specificity of G-UWP (78.6%; 95% CI 68.3 to 86.8) and UWP (75.0%; 95% CI 64.4 to 83.8) was comparable, but both were lower than that of RFP (98.8%; 95% CI 93.5 to 100.0; p<0.05).ConclusionNon-mydriatic UWP images can be used to detect RNFLD. Non-mydriatic G-UWP showed comparable sensitivity but lower specificity to conventional RFP. Non-mydriatic G-UWP could be used as a convenient and useful diagnostic tool for screening glaucoma in clinical settings.

A Doubly Green Separation Process: Merging Aqueous Two-Phase Extraction and Supercritical Fluid Extraction

Aqueous two-phase extraction (ATPE) is a green separation technique which uses mixtures of water and environmentally benign polymers such as polyethylene glycol (PEG) as solvents. One of the challenges in implementing this extraction on an industrial scale is finding a suitable method for the isolation of target compounds from water-polymer solutions after the extraction, without diminishing ecological benefits of the method. In this paper, we propose using another green separation technique, supercritical fluid extraction (SFE), for the back-extraction of low molecular weight medium polarity compounds from ATPE solutions. Experiments with two model compounds, caffeine and benzoic acid, showed principal applicability of SFE for this task. Pressure (100–300 bar) and temperature (35–75 °C) of supercritical carbon dioxide play a major role in defining extraction capability. Extraction ratios of 35% for caffeine and 42% for benzoic acid were obtained at high fluid pressure and moderate temperature at 1:6 volume phase ratio. That gives an estimation of 10–20 theoretical steps required for complete exhaustive extraction from the ATPE solution, which is readily achievable in standard counter-current column SFE. Combining these two green methods together not only serves as an environmentally friendly method for the isolation of valuable low molecular weight compounds from diluted water solutions, but also allows for simple, energy effective recuperation of ATPE solvents.