Green Deep Eutectic Solvents for Microwave-Assisted Biomass Delignification and Valorisation

Aiming to fulfil the sustainability criteria of future biorefineries, a novel biomass pretreatment combining natural deep eutectic solvents (NaDESs) and microwave (MW) technology was developed. Results showed that NaDESs have a high potential as green solvents for lignin fractionation/recovery and sugar release in the following enzymatic hydrolysis. A new class of lignin derived NaDESs (LigDESs) was also investigated, showing promising effects in wheat straw delignification. MW irradiation enabled a fast pretreatment under mild condition (120 °C, 30 min). To better understand the interaction of MW with these green solvents, the dielectric properties of NaDESs were investigated. Furthermore, a NaDES using the lignin recovered from biomass pretreatment as hydrogen bond donor was prepared, thus paving the way for a “closed-loop” biorefinery process.     

Wheat straw lignin extraction with bio-based solvents using enabling technologies

Two bio-based solvents, natural deep eutectic solvents (NaDESs) and γ-valerolactone (GVL), have been used under microwave (MW), and ultrasound (US) irradiation to design an efficient and sustainable process for wheat straw delignification and have been compared with the traditional alkali procedure. Best delignification (45%) was achieved with a three-component NaDES (lactic acid/glycerol/choline chloride) under MW irradiation (at 120 °C in 30 min), with solid/liquid ratio of 1:50. A GVL/water mixture (8:2) also gave an efficient delignification (27%) under US irradiation (40 kHz, 200 W) at 50 °C for 60 min. Analytical pyrolysis (Py) coupled with GC/MS/FID, provides valuable information on the extracts’ chemical profile. DPPH and Folin–Ciocalteu tests highlighted the efficiency of MW- and US-assisted extraction as well as the extracts quality. The highest antioxidant activity for the NaDES extracts was obtained under US irradiation.     

Optimization of an Ultrasound-Assisted Extraction Method for the Analysis of Major Anthocyanin Content in Erica australis Flowers

Erica australis plants have been used in infusions and folk medicine for years for its diuretic and antiseptic properties and even for the treatment of infections. In addition, a recently published thorough study on this species has demonstrated its antioxidant, antibiotic, anti-inflammatory, anticarcinogenic and even antitumoral activities. These properties have been associated with the high content of anthocyanins in E. australis leaves and flowers. The aim of the present research is to optimize an ultrasound-assisted extraction methodology for the recovery of the anthocyanins present in E. australis flowers. For that purpose, a Box Behnken design with response surface methodology was employed, and the influence of four variables at different values was determined: namely, the composition of the extraction solvents (0–50% MeOH in water), the pH level of those solvents (3–7), the extraction temperature (10–70 °C), and the sample:solvent ratio (0.5 g:10 mL–0.5 g:20 mL). UHPLC-UV-vis has been employed to quantify the two major anthocyanins detected in the samples. The extraction optimum conditions for 0.5 g samples were: 20 mL of solvent (50% MeOH:H₂O) at 5 pH, with a 15 min extraction time at 70 °C. A precision study was performed and the intra-day and inter-day relative standard deviations (RSDs) obtained were 3.31% and 3.52%, respectively. The developed methodology has been successfully applied to other Erica species to validate the suitability of the method for anthocyanin extraction.     

Optimization of the extraction process of flavonoids from Trollius ledebouri with natural deep eutectic solvents

In recent years, natural deep eutectic solvents have been favored greatly due to their environment friendly, mild biological toxicity and simple biodegradability. Natural deep eutectic solvents gradually applied for the extracting bioactive compounds from natural products efficiently. In this study, 20 natural deep eutectic solvents were prepared and their physical and chemical properties were tested. The ultrasonic-assisted extraction method was used to extract flavonoids from Trollius ledebouri and high-performance liquid chromatography-ultraviolet was applied to examine two main bioactive flavonoids (orientin and vitexin). Compared with traditional solvents (water and 60% ethanol solution), natural deep eutectic solvents composed of L(-)-proline and levulinic acid (molar ratio 1:2) show a super extraction efficiency. On this basis, the response surface method was used to optimize the extraction temperature, extraction time, water contents, and solid–liquid ratio. As a consequence, the extraction temperature 60℃, extraction time 18 min, water content 14% (v/v), and the solid–liquid ratio 48 mL·g⁻¹ were chosen as the best extraction process. This study shows that natural deep eutectic solvents can effectively extract flavonoids from T. ledebouri, laying a foundation for the further application of natural deep eutectic solvents to extract bioactive compounds from natural products.     

Extract with high 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibitory capability from pericarp and seed of mangosteen (Garcinia mangostana L.) using microwave-assisted extraction (MAE) two-phase solvent technique

The human body needs compounds that are antioxidants to prevent oxidative stress. Some parts of the mangosteen fruit (Garcinia mangostana L.) have been known as sources of bioactive compounds that have antioxidant properties. The pericarp and seeds of mangosteen were extracted using the MAE method to produce the extract with the greatest antioxidant activity. There are two types of solvent mixtures used in the extraction process: single-phase and two-phase solvents. The solvents used were ethanol (EtOH), ethyl acetate (EtOAc), isopropyl alcohol (IPA), and water. First, utilizing dried mangosteen pericarp powder as the raw material, a study was undertaken to determine the ideal operating conditions for the MAE process. A one-factor-at-a-time approach was used to find the best operating conditions. A mixture of solvents with varied ratios (mL/mL), extraction temperature (°C), extraction time (min), and solid to solvent ratio (g/mL) were applied as independent variables. Then, dried mangosteen seed powder extraction was carried out based on the best-operating conditions previously achieved. The DPPH scavenging activity, total phenolic content (TPC) value, and α-mangostin content of the two extracts were compared. It was discovered that the mangosteen pericarp extract showed higher antioxidant activity (IC₅₀ DPPH = 9.40 µg/mL) than the mangosteen seed extract (IC₅₀ DPPH = 37.54 µg/mL), even slightly better than ascorbic acid (IC₅₀ DPPH = 10.47 µg/mL). The best extract was produced from the bottom phase of two-phase solvent system (EtOAc:EtOH:Water 2:1:2), with an MAE temperature of 50 °C, a time of 4 min, and a solid-to-solvent ratio of 1:16. The TPC value of the best extract is 903.54 mgGAE/g extract, with a yield of 16.53 % and an α-mangostin concentration of 0.11 %.     

Appraisal of wild fig fruits for nutra-pharmaceutical and biological attributes

The fruits of wild fig, native to Soon valley of Pakistan, were appraised for phenolic compounds and high-value nutrients. These fruits were shade-dried and extracted with different solvents of varying polarity to recover a wide range of antioxidant components, where hydroxyethanol exhibited highest extraction yield of antioxidant compounds. Among others, hydroxyethanol-derived crude concentration extracts (CCEs) and phenolic rich fractions (PRFs) showed greater amount of total phenolic, flavonoids and superior biological properties. The fruits of tested fruits were found to possess potassium (11.34 g/kg) and calcium (4.19 g/kg) as major elements, glucose (5.63g/100g DW) as dominant natural sugar and acetic acid (2.40 mg/100 g of dry matter) as principal organic acid. There was a considerable (p < 0.05) variation in phenolic content and biological properties of various extracts recovered with different solvents. Furthermore, the biological properties of tested fruits were found to be significantly correlated with their intrinsic total phenolic content (TPC) and total flavonoid content (TFC). Based upon the findings of present study, the fruits of wild fig could be treated as promising source of beneficial nutrients and potent phenolic components for their applications in the development of nutrapharmaceuticals.     

Enhanced Extraction Efficiency of Flavonoids from Pyrus ussuriensis Leaves with Deep Eutectic Solvents

In this study, deep eutectic solvents (DESs) were synthesized using different ratios of choline chloride (CC) and dicarboxylic acids, and their eutectic temperatures were determined. The DES synthesized using CC and glutaric acid (GA), which showed a higher extraction efficiency than conventional solvents, was used for the extraction of flavonoid components from Pyrus ussuriensis leaves (PUL), and the extraction efficiency was evaluated using the response surface methodology. The flavonoid components rutin, hyperoside, and isoquercitrin were identified through high-performance liquid chromatography (HPLC), equipped with a Waters 2996 PDA detector, and HPLC mass spectrometry (LC-MS/MS) analyses. The optimum extraction was achieved at a temperature of 30 °C using DES in a concentration of 30.85 wt.% at a stirring speed of 1113 rpm and an extraction time of 1 h. The corresponding flavonoid content was 217.56 μg/mL. The results were verified by performing three reproducibility experiments, and a high significance, with a confidence range of 95%, was achieved. In addition, the PUL extracts exhibited appreciable antioxidant activity. The results showed that the extraction process using the DES based on CC and GA in a 1:1 molar ratio could effectively improve the yield of flavonoids from PUL.     

Green and highly extraction of phenolic compounds and antioxidant capacity from kinkeliba (Combretum micranthum G. Don) by natural deep eutectic solvents (NADESs) using maceration,ultrasound-assisted extraction and homogenate-assisted extraction

Kinkeliba (C. micranthum) is a tropical plant widely used for its tremendous phytochemicals and biological activities. In the present study, three green carboxylic acid-based natural deep eutectic solvents (NADESs) were used to assess the extraction of phenolic compounds in terms of total phenolic content (TPC), total flavonoid content (TFC), individual phenolic compounds and antioxidant capacity (DPPH and FRAP assays) from dried C. micranthum leaves. For the synthesis of NADESs choline chloride was used as hydrogen bond acceptors (HBA) in combination with lactic acid (ChLa), acetic acid (ChAa) and tartaric acid (ChTa) as hydrogen bond donors (HBDs). The conventional solvents including distilled water, pure methanol and pure ethanol were used for comparison. Three extraction methods including maceration extraction (ME), homogenate-assisted extraction (HAE) and ultrasound-assisted extraction (UAE) were tested to determine the best extraction conditions. The solvents combined with the extraction methods were successfully applied for the recovery of phenolic compounds from C. micranthum leaves. ChLa exhibited the highest performance giving the TPC (21.12 ± 0.13–23.62 ± 0.58 mg GAE/g, followed by ChAc (15.49 ± 0.13–18.85 ± 0.39 mg GAE/g), water (17.08 ± 0.32–18.13 ± 0.13 mg GAE/g), ChTa (14.49 ± 0.26–17.44 ± 0.19 mg GAE/g), methanol (7.46 ± 0.45–11.64 ± 0.32 mg GAE/g) and ethanol (2.88 ± 0.39–4.60 ± 0.39 mg GAE/g), respectively. For TFC, ChLa (4.38 ± 0.09–5.01 ± 0.09 mg ECE/g) was the most prominent solvent, followed by ChAc (2.84 ± 0.04–5.01 ± 0.36 mg ECE/g), methanol (1.93 ± 053–4.85 ± 0.04 mg ECE/g), ethanol (1.49 ± 0.36–4.16 ± 0.04 mg ECE/g), ChTa (1.09 ± 0.04–3.22 ± 0.13 mg ECE/g) and water (1.15 ± 0.04–1.37 ± 0.44 mg ECE/g), respectively. The acidic NADESs especially ChLa and ChAa exhibited the best efficiencies compared to the conventional solvents. Furthermore, UAE and HAE provided good extraction efficiency in a short extraction time (30 min) in terms of the TPC, TFC, individual phenolic compounds and the antioxidant capacity compared to ME which gave a similar yield with 12 h of extraction time. Principal component analysis (PCA) showed that C. micranthum extracts could clearly be discriminated in terms of phytochemical compounds and antioxidant capacity and UAE, HAE or ME combined with ChLa ChAc or ChTa were the best choices to higher extraction efficiency.     

Development and Box–Behnken design optimization of a green extraction method natural deep eutectic solvent-based for phenolic compounds from barley malt rootlets

In recent years, attention has been turned finding new sources of phenolic compounds, antioxidant molecules, main by-products from the agri-food chain like barley malt rootlets (BMRs). Traditionally, phenolic compounds are extracted from food matrices using different procedures, for example, solid–liquid, liquid–liquid, or solid-phase extraction techniques employing organic solvents. With the advent of green chemistry, attention has been paid to the search for green, nontoxic, inexpensive, and nonflammable solvents and the natural deep eutectic solvents (NADESs) respect these characteristics. The aim of this project was to develop and optimize an environmentally friendly, inexpensive, and rapid extraction method for phenolic compounds from BMRs using natural DESs as extractive solvents. Several natural DESs were tested as extractive solvents and, among them, the best results in terms of total phenolic content were obtained using a choline chloride-malic acid (1:2 molar ratio)-based mixture. Box–Behnken experimental design guaranteed the extraction of 9.51 ± 0.83 gallic acid equivalent/g of BMRs, under the following optimal extraction conditions: 1:21 solid-to-liquid ratio, 80°C as extraction temperature, 43 min as the time of extraction, and 29% as a percentage of added water in the NADESs. Phenolic acids and flavonoids were detected in the BMRs extract through HPLC-PDA/MS analysis.     

A simple and efficient sample preparation for taxanes in Taxus chinensis needles with natural menthol‐based aqueous deep eutectic solvent

Taxanes are natural anticancer constituents, and the sample preparation from matrix normally depends on organochlorine solvents. In this study, green and natural menthol‐based aqueous deep eutectic solvent was synthesized and used for sample preparation for taxanes. Five key parameters were optimized and the optimal preparation conditions were as follows: menthol/1‐propanol ratio 1:1 (mol/mol), solid–liquid ratio 1:30 g/mL, extraction time 30 min, ultrasonic power 250 W, and water content 80%. Under the above conditions, the total extraction efficiency of seven main taxanes was 1.25‐ to 1.44‐fold to the conventional methods. In addition, a high‐performance liquid chromatography method with C₁₈ column was established for quantitation of seven main taxanes in <25 min, which had excellent linearity (R² > 0.9986), precision (relative standard deviation < 3.00%), repeatability (relative standard deviation < 3.69%), and recovery (90.26–109.00%). This method performed the extraction, and enrichment processes simultaneously, and it had advantages such as high extraction efficiency, simple operation, low cost, and eco‐friendliness. This work indicated that the natural menthol‐based deep eutectic solvent aqueous could be an excellent alternative to the sample preparation from Taxus or other plants.     

Optimization of Two Eco-Friendly Extractions of Black Medick (Medicago lupulina L.) Phenols and Their Antioxidant,Cosmeceutical, α-Glucosidase and α-Amylase Inhibitory Properties

Medicago lupulina is an ancient edible plant from the Fabaceae family. In this work, two eco-friendly methods for extraction of bioactive phenolics from M. lupulina were developed using mixtures of water with two non-toxic, skin- and environmentally-friendly polyol solvents: glycerol and polypropylene glycol. Ultrasound-assisted extractions were optimized using a Box–Behnken design. The independent variables were the concentration of organic solvent in water (X₁), extraction temperature (X₂) and time (X₃), while the response was phenolic content. The optimum conditions for extraction of polyphenols were (X₁, X₂, X₃): (45%, 70 °C, 60 min) and (10%, 80 °C, 60 min) for glycerol and polypropylene glycol extraction, respectively. The extracts prepared at optimum conditions were rich in phenolic compounds, mainly derivatives of apigenin, kaempferol, luteolin, quercetin, caffeic and ferulic acid, as well as coumestrol. Their cosmeceutical and antidiabetic activity was tested. Both extracts demonstrated notable antioxidant, anti-lipoxygenase and anti-α-amylase activity. In addition to those activities, the glycerol extract efficiently inhibited protein coagulation, elastase and α-glucosidase activity. Glycerol present in the extract displayed enzyme-inhibiting activity in several assays and supported the action of the bioactive constituents. Thus, the optimized glycerol extract is a desirable candidate for direct incorporation in antidiabetic food supplements and cosmeceutical products.     

Screening of ionic liquids for extraction of flavonoids from heather

Room temperature ionic liquids are novel solvents with the specific properties that makes them of interest for application for extraction for a wide range of compounds. In this work extraction efficiency of flavonoids from heather flowers using ionic liquids based on imidazolium cation were evaluated and compared with organic solvents. It was found that the anion of ionic liquid significantly influence the extraction yields. Flavonoid content as well as antioxidant activity based on radical scavenging on 1,1-diphenul-2-pirylhydrazyl radicals and cupric reducing antioxidant capacity increased in the order: [Bmim]PF₆ < [Bmim]BF₄ < [Bmim]Cl. The obtained extraction yield using [Bmim]Cl were higher than reported for 60% ethanol and ethyl acetate under similar conditions, thus, may be helpful for better utilization of heather flowers as the potential pharmaceutical and nutraceutical ingredients.     

Metal-organic framework functionalized with deep eutectic solvent for solid-phase extraction of Rhodamine 6G in water and cosmetic products

An NH₂-MIL-53(Al)-DES(ChCl-Urea) nanocomposite was synthesized for extraction and determination of Rhodamine (Rh) 6G from environmental and cosmetic samples. The deep eutectic solvent (DES) was prepared by mixing choline chloride and urea in a mole ratio of 1:2. NH₂-MIL-53(Al)-DES(ChCl-Urea) nanocomposite was synthesized using the impregnation method at a ratio of 60:40 (w/w). The optimum conditions were determined after NH₂-MIL-53(Al)-DES(ChCl-Urea) characterization was performed. The optimum conditions were determined as pH 8, adsorbent amount of 15 mg, total adsorption-desorption time of 6 min, and enrichment factor of 20. The recovery values of the solid-phase extraction method for water and cosmetic samples under optimum conditions were between 95% and 106%. NH₂-MIL-53(Al)-DES(ChCl-Urea) nanocomposite was an economically advantageous adsorbent because of its reusability of 15 times. All analyses were performed using the ultraviolet-visible spectrophotometer. The linear range, limit of detection, and limit of quantification of the method were 100–1000, 9.80, and 32.68 μg/L, respectively. The obtained results showed that the synthesized nanocomposite is a suitable adsorbent for the determination of Rh 6G in water and cosmetic samples. The real sample applications were verified with the high-performance liquid chromatography system.     

Size-controlled synthesis of CuO–ZrO<Subscript>2</Subscript> nanoparticles prepared through reverse micelle method

In this research, CuO–ZrO₂ nanoparticles are synthesized using microreactors made of surfactant/water/cyclohexane microemulsions. The effect of different microemulsion variables on the particle size and its distribution, such as water-to-surfactant molar ratio (W ₀) and different surfactants are discussed. Three different surfactant types including cationic (CTAB), anionic (AOT), and nonionic (Brij56) are used. Also a different amount of water to surfactant in nano composite synthesis is used. The powders were characterized by DTA/TG, XRD, SEM, EDS, TEM and BET techniques and their physical properties are compared. The results show a decrease of particles size in presence of cationic surfactant. Narrow particles size distribution of the resultant CuO–ZrO₂ nanocomposite in presence of cationic surfactant, anionic and nonionic surfactant is compared. Also for AOT surfactant, by raising water to surfactant molar ratio the particles size is increased and the optimum ratio is H₂O: Surfactant = 0.32:0.055, respectively.     

Extraction and determination of bioactive flavonoids from Abelmoschus manihot (Linn.) Medicus flowers using deep eutectic solvents coupled with high‐performance liquid chromatography

A highly efficient and ecofriendly extraction method using deep eutectic solvents was developed to extract bioactive flavonoids from Abelmoschus manihot (Linn.) Medicus flowers. First, a series of deep eutectic solvents using choline chloride as hydrogen bond acceptor with different hydrogen bond donors was successfully synthesized. Then, the types of deep eutectic solvents and the extraction conditions for bioactive flavonoids (hyperoside, isoquercitrin, and myricetin) were optimized based on the flavonoids extraction efficiencies. The optimized deep eutectic solvent for hyperoside and isoquercitrin extraction was composed of choline chloride and acetic acid with a molar ratio of 1:2. The optimized deep eutectic solvent for myricetin extraction was composed of one mole of choline chloride and two moles of methacrylic acid. The optimal extraction conditions were set as: solid to solvent ratio, 35:1 (mg/mL); extraction time, 30 min; extraction temperature, 30°C. Qualitative and quantitative analysis were performed using ultra high performance liquid chromatography with tandem mass spectrometry and high‐performance liquid chromatography. And the extraction efficiencies of hyperoside, isoquercitrin, and myricetin under optimal extraction conditions were calculated as 11.57, 5.64, and 1.11 mg/g, much higher than those extracted by traditional extraction solvents. Therefore, the prepared deep eutectic solvents can be selected as alternative solvent to extract bioactive flavonoids.     

Microwave-Assisted Extraction of Curcuma longa L. Oil: Optimization,Chemical Structure and Composition,Antioxidant Activity and Comparison with Conventional Soxhlet Extraction

Curcuma root (Curcuma longa L.) is a very important plant in gastronomy and medicine for its unique antiseptic, anti-inflammatory, antimicrobial and antioxidant properties. Conventional methods for the extraction of curcuma oil require long extraction times and high temperatures that can degrade the active substances. Therefore, the objectives of the present study were: (i) first, to optimize the extraction yield of curcuma oil by applying a Box-Behnken experimental design using surface response methodology to the microwave-assisted extraction (MAE) technique (the independent variables studied were reaction time (10–30 min), microwave power (150–200 W) and curcuma powder/ethanol ratio (1:5–1:20; w/v); and, (ii) second, to assess the total phenolic content (TPC) and their antioxidant activity of the oil (at the optimum conditions point) and compare with the conventional Soxhlet technique. The optimum conditions for the MAE were found to be 29.99 min, 160 W and 1:20 w/v to obtain an optimum yield of 10.32%. Interestingly, the oil extracted by microwave-assisted extraction showed higher TPC and better antioxidant properties than the oil extracted with conventional Soxhlet technique. Thus, it was demonstrated that the method applied for extraction influences the final properties of the extracted Curcuma longa L. oil.     

Investigation on Ultrasound-Assisted Extraction and Separation of Enduracidin from <Emphasis Type="Italic">Streptomyces</Emphasis> sp. NJWGY3665

Ultrasound-assisted extraction of enduracidin from Streptomyces sp. NJWGY3665 was studied. The effects of various factors on the yield of target components were investigated. The results showed that the extraction by ultrasound-assisted extraction is four times faster than those by conventional solvent extraction. The results also indicated that fast extraction rate was obtained in the first 30 min, and the maximum yield was obtained at the power of 150 W. The effects of other factors such as different solvents, solvent concentration, solvent to solid ratio, and extraction batches on the field were also discussed. The optimum conditions were found at solvent of methanol, time of 30 min, power of 150 W, pH of 7.0, solvent to solid ratio of 50 ml/g, solvent concentration of 70% and extraction batches of four times.     

Statistical Optimization of Flavonoid and Antioxidant Recovery from Macerated Chinese and Malaysian Lotus Root (Nelumbo nucifera) Using Response Surface Methodology

In this study, the combination of parameters required for optimal extraction of anti-oxidative components from the Chinese lotus (CLR) and Malaysian lotus (MLR) roots were carefully investigated. Box–Behnken design was employed to optimize the pH (X₁: 2–3), extraction time (X₂: 0.5–1.5 h) and solvent-to-sample ratio (X₃: 20–40 mL/g) to obtain a high flavonoid yield with high % DPPH_sc free radical scavenging and Ferric-reducing power assay (FRAP). The analysis of variance clearly showed the significant contribution of quadratic model for all responses. The optimal conditions for both Chinese lotus (CLR) and Malaysian lotus (MLR) roots were obtained as: CLR: X₁ = 2.5; X₂ = 0.5 h; X₃ = 40 mL/g; MLR: X₁ = 2.4; X₂ = 0.5 h; X₃ = 40 mL/g. These optimum conditions gave (a) Total flavonoid content (TFC) of 0.599 mg PCE/g sample and 0.549 mg PCE/g sample, respectively; (b) % DPPH_sc of 48.36% and 29.11%, respectively; (c) FRAP value of 2.07 mM FeSO₄ and 1.89 mM FeSO₄, respectively. A close agreement between predicted and experimental values was found. The result obtained succinctly revealed that the Chinese lotus exhibited higher antioxidant and total flavonoid content when compared with the Malaysia lotus root at optimum extraction condition.     

Extraction of diclofenac by SiO2‐NH2@Fe3O4 and its determination: Central composite design

In this work, magnetic nanoparticles (Fe₃O₄) were prepared by simple co‐precipitation method in aqueous medium and then subsequently modified with tetraethyl orthosilicate and 3‐aminopropyl triethylenesilane. The properties of the particles were characterized by FTIR spectroscopy X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy. The SiO₂‐NH₂@Fe₃O₄ particles were successfully applied to simultaneously enrich and separate diclofenac from water, urine, and plasma samples. The method, which takes the advantages of both nanoparticle adsorption and magnetic phase separation from the sample solution, could avoid some of the time‐consuming experimental procedures related to the traditional solid phase extraction. The main parameters affecting extraction and desorption efficiency such as pH, amount of SiO₂‐NH₂@Fe₃O₄, volume of desorption solvent, and extraction time were screened. The significant variables were optimized by using central composite design. At optimum conditions values of variables set as pH = 4, 10 mg SiO₂‐NH₂@Fe₃O₄, 0.5 mL methanol, and 15 min extraction time and then the extracted diclofenac were injected to HPLC for analysis. The linear response (r² > 0.9992) was obtained in the range of 0.004–15 µg/mL with detection limit 0.0012 µg/mL and extraction recovery was in the range of 92–96% with RSD < 5% (n = 6).     

Successive uranium and thorium adsorption from Egyptian monazite by solvent impregnated foam

The present work deals with uranium and thorium recovery from the Egyptian monazite sulfate leach liquor using the extraction chromatography technique (solvent impregnated material), where tributylamine (TBA) and di-n-octylamine (DOA) solvents were impregnated onto foam uranium and thorium separate recovery. The calculated theoretical capacities of the latter solvents were about 1.4 gU/g foam and 1.6 gTh/g foam, respectively. The attained uranium and thorium adsorption efficiencies (using ion-exchange columnar technique) were about 75 and 70% of its theoretical capacities, respectively. Using 1 M NaCl–0.1 M H₂SO₄ and 2 M H₂SO₄ as eluent solutions for uranium and thorium from the loaded solvents impregnated foam gave 95.8 and 98.7% elution efficiencies, respectively.