β-Cyclodextrin Derivative Grafted on Silica Gel Represents a New Polymeric Sorbent for Extracting Nitisinone from Model Physiological Fluids

Nitisinone (NTBC) is used in the treatment of disorders affecting the tyrosine pathway, including hereditary tyrosinemia type I, alkaptonuria, and neuroblastoma. An inappropriate dosage of this therapeutic drug causes side effects; therefore, it is necessary to develop a rapid and sensitive method to monitor the content of NTBC in patients’ blood. This study aimed to develop anew polymeric sorbent containing β-cyclodextrin (β-CD) derivatives grafted on silica gel to effectively extract NTBC from model physiological fluids. The inclusion complex formed between β-CD and NTBC was examined by proton nuclear magnetic resonance spectroscopy. The novel sorbents with derivatives of β-CD were prepared on modified silica gel using styrene as a comonomer, ethylene glycol dimethacrylate as a crosslinking agent, and 2,2′-azo-bis-isobutyronitrile as a polymerization initiator. The obtained products were characterized via Fourier transform infrared spectroscopy and then used as sorbents as part of a solid phase extraction technique. High NTBC recovery (70%indicated that the developed polymeric sorbent may be suitable for extracting this compound from patients’ blood samples.

Biotesting of petroleum sorbents on the basis of polymer waste

Introduction. Biotesting is considered to be an effective method of assessing the potential hazard of chemical, physical or biological effects on an ecosystem. Biotesting is carried out experimentally using, as a rule, standardized laboratory test systems, by recording changes in biologically important indicators (test reactions) under the influence of the studied samples. Hydrobionts act as biologically sensitive sensors: protozoa, algae, crustaceans, mollusks, fish, etc. Biotic indicators can provide information about the transformation of the ecosystem, the state of organisms and the degree of acceptability of influences to preserve the diversity of life forms and their balanced development. During the bioremediation of oil-contaminated water bodies at low temperatures and at high water flow rates (mountain streams) there are significant difficulties and traditional approaches and sorbents can not always be applied. Therefore, it is necessary to develop new non-traditional sorbents. At the same time, it is ecologically expedient to use multi-ton waste of packaging polymeric materials extracted from solid household waste, which are biologically and chemically inert, have unique sorption properties and are suitable for multiple use. Two ecologically dangerous problems have been solved - water pollution by oil products and the growth of polymer packaging in the share of household waste. The goal is to biotest the change of oil-contaminated environment during purification in model conditions with the use of polymer hydrophobic sorbents from raw materials extracted from solid household waste as bioremediators. Research objectives: to establish biological and toxicological safety of the use of secondary polymer raw materials from packaging waste as oil sorbents; to investigate the safety of using environmentally friendly surfactants from vegetable raw materials common in Ukraine to increase the extraction of petroleum products from water. Methods and techniques: toxicological - determination of water toxicity on Daphnia magna acute according to DSTU 4173: 2003 (ISO 6341: 1996, MOD) and chronic according to DSTU 4166: 2003 (ISO 10706: 2000, MOD), photometric method for determining the amount of oil in water according to GOST 17.1.4.01-80. The research results show the effectiveness of hydrophobic polymer sorbents made from secondary polymer raw materials extracted from solid waste in water contaminated with petroleum products to ensure their localization-sorption. The mortality rates of daphnia in all samples with sorbents at the beginning of the experiment were much lower than in the control, because the bulk of the contaminant was adsorbed on the surface of hydrophobic sorbents. At the end of the experiment, the best result in terms of the number of viable daphnia was observed in the cut of a sorbent made of polypropylene, the surface of which is covered with surfactants extracted from Milnyanka medicinal (Saponaria officinalis L). In this sample, the mortality of the test culture is 23%, which is 32% less than the control - 72%. Conclusions. Studies of the impact on aquatic ecosystems and the toxic effect of developed petroleum sorbents on Daphnia magna Straus have established the effectiveness of hydrophobic polymeric sorbent in water contaminated with petroleum products, ensuring their localization-sorption. The mortality rates of daphnia in all studied samples of sorbents except the sorbent from PVC waste were significantly lower than in the control, because the bulk of the contaminant was adsorbed in the polymeric sorbent. Biotesting showed that the sorption material based on polymeric secondary raw materials did not have a toxic effect in the process of purification of water from hydrocarbons. Therefore, it can be considered promising as a basis for bioremediators and for further use in the purification of water bodies from dissolved and spilled petroleum products. However, further in-depth toxicological studies require PVC-based sorbents, although their effects have not gone beyond what is acceptable and it is necessary to study their behavior under the influence of temperature changes and the reaction of other test organisms.

SILVER(I) PRECONCENTRATION USING m-AMINOPHENOL CONTAINING SORBENT FROM AQUEOUS SOLUTIONS

The influence of sorption characteristics on the removal of silver(I) has been examined. The sorption capacity of chelating polymeric sorbent, based on maleic anhydride styrene copolymer modified with m-aminophenol, towards Ag(I) ions was studied. The pH of sorption was maximum at the value 6. With the increasing of initial metal concentration, sorption of silver(I) increases and reached maxima at val-ue 80∙10-3 M. At the final stage, the elution process of Ag(I) was established and find that HNO3 1 M is the best elution agent. Multiple use of the regenerated sorbent for sorption process is possible. This study shows that using of mentioned sorbent modified with m-aminophenol is effective for removal of silver(I) ions from aqueous solutions

Experimental Investigation of Desiccant Dehumidification Cooling System for Climatic Conditions of Multan (Pakistan)

In this study, experimental apparatus of desiccant dehumidification was developed at lab-scale, using silica gel as a desiccant material. Experimental data were obtained at various ambient air conditions, while focusing the climatic conditions of Multan (Pakistan). A steady-state analysis approach for the desiccant dehumidification process was used, and thereby the slope of desiccant dehumidification line on psychrometric chart (ϕ*) was determined. It has been found that ϕ* = 0.22 in case of silica gel which is lower than the hydrophilic polymeric sorbent, i.e., ϕ* = 0.31. The study proposed two kinds of systems, i.e., (i) standalone desiccant air-conditioning (DAC) and (ii) Maisotsenko-cycle-assisted desiccant air-conditioning (M-DAC) systems. In addition, two kinds of desiccant material (i.e., silica gel and hydrophilic polymeric sorbent) were investigated from the thermodynamic point of view for both system types, using the experimental data and associated results. The study aimed to determine the optimum air-conditioning (AC) system type, as well as adsorbent material for building AC application. In this regard, perspectives of dehumidification capacity, cooling capacity, and thermal coefficient of performance (COP) are taken into consideration. According to the results, hydrophilic polymeric sorbent gave a higher performance, as compared to silica gel. In case of both systems, the performance was improved with the addition of Maisotsenko cycle evaporative cooling unit. The maximum thermal COP was achieved by using a polymer-based M-DAC system, i.e., 0.47 at 70 °C regeneration temperature.

Polymeric Sorbent Sheets Coupled to Direct Analysis in Real Time Mass Spectrometry for Trace-Level Volatile Analysis—A Multi-Vineyard Evaluation Study

Etched polymeric sorbent sheets (solid-phase mesh-enhanced sorption from headspace (SPMESH) sheets) were recently described as an alternative to solid-phase microextraction (SPME) for rapid, parallel, multi-sample extraction and pre-concentration of headspace volatiles. In this report, a workflow was evaluated based on SPMESH sheet extraction followed by direct analysis in real time-mass spectrometry (DART-MS) using grape samples harvested from multiple commercial vineyards at different maturities. SPMESH sheet-DART-MS(-MS) was performed on two grape-derived odorants related to wine quality: 3-isobutyl-2-methoxypyrazine (IBMP) in Cabernet Sauvignon and Merlot grape homogenate (n = 86 samples) and linalool in Muscat-type grape juice samples (n = 18 samples). As part of the optimization process, an MS-MS method was developed for IBMP and an equilibration procedure prior to extraction was established for homogenate samples. Following optimization, we achieved good correlation between SPMESH sheet-DART-MS and SPME-GC-MS for both IBMP (range by GC-MS = < 2 ng/L to 28 ng/L, R2 = 0.70) and linalool (range by GC-MS = 135 to 415 μg/L, R2 = 0.66). The results indicate SPMESH sheet-DART-MS is suitable for rapid measurements of trace level volatiles in grapes.