Removal of the selected pesticides from a water solution applying hollow fiber liquid-liquid membrane extraction

A supported liquid membrane extraction of different pesticides (acetamiprid, dimethoate, imidacloprid, linuron, and tebufenozide) from an aqueous solution containing 20 mg dm–3 of each pesticide by 5% TOPO (tri-n-octylphosphine oxide) in DHE (di-n-hexyl ether) has been investigated in a hollow fiber contactor having an aqueous feed/organic interfacial area of 15.4 cm2. In a single-pass operation, the maximum removal efficiency of 95% was achieved for the most nonpolar (log P = 4.38) pesticide tebufenozide at the feed flow rate of 0.5 cm3 min–1. The diffusion through the boundary layer of the feed stream was a rate-controlling step in the extraction of nonpolar pesticides (linuron and tebufenozide) with a mass-transfer coefficient in the feed stream being proportional to the feed flow rate raised to the power of 0.51–0.57. The maximum overall mass-transfer coefficient based on the feed phase of KF = 0.18 cm min–1 was obtained for tebufenozide at the feed flow rate of 1.8 cm3 min–1. The organic phase entrapped in the membrane pores offered a major resistance to the mass transfer of polar pesticides (log P < 1) and accounted for 85% of the overall mass-transfer resistance for imidacloprid at 1.8 cm3 min–1. The pesticides removed from the feed solution were almost completely accumulated in the organic phase but were recovered from the membrane pores to a large extent (50–90%) by rinsing the membrane with methanol after extraction

Membrane pertraction of Lu(III) with di(2-ethylhexyl) phosphoric acid as a carrier

Introduction: In a supported liquid membrane (SLM) extraction, also named pertraction, target analytes are extracted from an aqueous feed sample, the ‘donor phase’, into an organic phase entrapped in micropores of a hydrophobic support membrane, and further transferred into an acceptor phase. Different approaches and applications of SLM extraction are described in scientific literature such as analysis of drugs, pesticides, metal ions, organic pollutants1 etc. Though a number of SLM extraction investigations on metal ion separation have been reported in literature2, very little work has been doneon the application of membrane extraction for radionuclide separation3,4. Radiopharmaceuticals are drugs labeled with radionuclide which are used in various diagnostic and therapeutic applications in nuclear medicine. The interest for the usage of radiolabeled peptides and monoclonal antibodies for therapy is growing in the last decade. Also, radioactive isotope 177Lu and labeled radiopharmaceuticals are being increasingly used as therapeutic agents in nuclear medicine5. Although the percentage of binding the radionuclide to a target molecule is usually very high (~ 98%), there is always a fraction of the free radionuclide. This is very important in the case of radiopharmaceutical for radiotherapy. The single dose for radiotherapy can be very high (up to 30 GBq), thus the absolute amount of free radionuclide can be significant. The free 177Lu(III) accumulates in bones, thus is very important to separate free 177Lu(III) from the labeled compound. The most commonly applied technique for this purification is chromatography. Except that, the application of SLM extraction with flat membrane for separation labeled compound and free 177Lu(III) was proposed and studied in our previous paper4. Recently, SLM extraction has been simplified by introduction of a SLM extraction in a single hollow fiber without any special device6. The SLM extraction in a single hollow fibre can be operated only in a batch mode without any phase flow rate. Apart from common characteristics of membrane extraction such as large interfacial areas, low consumption of organic solution, good opportunity for process automation etc, SLM in a single hollow fibre has additional advantages such as easy to handle equipment, no special device to avoid accidental release of radioactive material and a sample volume as low as 1 cm3. The aim of the present study was to investigate the pertraction of Lu(III) from an aqueous phase by applying miniaturized SLM extraction in a single hollow fibre. The influence of the donor pH, content of the carrier in the organic phase and the time of extraction on lutetium extraction and stripping were investigated

Comparison of static and continuous hollow fibre liquid-phase extraction of lutetium

This work is a comparative study of the efficiency of the lutetium (III) extraction in membrane-assisted liquid-phase extraction (LPE) carried out under static and continuous operation mode using di(2-ethylhexyl)phosphoric acid (DEHPA) as a carrier. The removal of Lu(III) from the donor solution and its recovery into the acceptor phase were compared for the two operation modes investigated. Additionally, the applicability of both systems for purification of 177Lu-radiopharmaceutical was discussed

Liquid phase membrane extraction of targeted pesticides from manufacturing wastewaters in a hollow fiber contactor with feed-stream recycles

A two-phase membrane extraction in a hollow fibre contactor with feed-stream recycle was applied to remove selected pesticides (tebufenozide, linuron, imidacloprid, acetamiprid and dimethoate) from their mixed aqueous solutions. The contactor consisted of 50 polypropylene hollow fibers impregnated with 5% tri-n-octylphosphine oxide in di-n-hexyl ether. For low polar pesticides with log P ˃ 2 (tebufenozide and linuron), the maximum removal efficiency increased linearly from 85 to 96% with increasing the feed flow rate. The maximum removal efficiencies of more polar pesticides were significantly higher under feed recirculation (86%) than in a continuous single pass operation (30%). It was found from the Wilson's plot that the mass transfer resistance of the liquid membrane can be neglected for low polar pesticides. The pesticide removals from commercial formulations were similar to those from pure pesticide solutions, indicating that built-in adjuvants did not affect the extraction process

Separation of yttrium from strontium by hollow fibre supported liquid membrane containing di(2-ethylhexyl)phosphoric acid

Separation of Y(III) from Sr(II) was performed using the hollow fibre membrane contactor operated in a recirculation mode. The steady-state was established after ~5 h of operation and the maximum removal of Y(III) from the donor to the acceptor was achieved at the donor flow rate of 4.7 cm3 min-1 . The investigated system showed promising results as a method which could be potentially applied for the preparation of 90Sr/ 90Y generator system

Novel 90Sr-90Y generator system based on a cross-flow hollow fiber supported liquid membrane contactor

Separation of yttrium(III) from strontium(II) with 15% (v/v) di(2-ethylhexyl)phosphoric acid (DEHPA) in dodecane was carried out in a hollow fiber supported liquid membrane (SLM) extraction system operated under closed-loop recirculation of the donor and acceptor phase. The donor phase was a mixture of 5.7 mmol dm-3 of Sr(II) and 0.23 mmol dm-3 of Y(III) in 0.1 mol dm-3 HCl, the acceptor solution was 3 mol dm-3 HCl, and the donor to acceptor phase volume ratio was 6.2. At the donor flow rate of 4.7 cm3 min-1 and the acceptor flow rate of 0.8 cm3 min-1, the yield of Y(III) in the acceptor phase reached 60% after 360 min with a molar ratio of Y(III) to Sr(II) in the acceptor of 250:1, as compared to 1:25 in the donor phase. The yield of Y(III) was 72% at the acceptor flow rate to 1.9 cm3 min-1, but a breakthrough of Sr(II) through liquid membrane increased from 0.02 to 0.2%

Pertraction of Lu(III) in a hollow fibre contactor

Pertraction of Lu(III) in a hollow fibre contacto

Separation of yttrium from strontium by hollow fibre supported liquid membrane containing di(2-ethylhexyl)phosphoric acid

Separation of Y(III) from Sr(II) was performed using the hollow fibre membrane contactor operated in a recirculation mode. The steady-state was established after ~5 h of operation and the maximum removal of Y(III) from the donor to the acceptor was achieved at the donor flow rate of 4.7 cm3 min-1. The investigated system showed promising results as a method which could be potentially applied for the preparation of 90Sr/90Y generator system

Liquid-phase microextraction in a single hollow fibre: determination of mass transfer coefficient

In this study, the mass transfer coefficient of two local anesthetics in liquidphase microextraction (LPME), which is performed in a single hollow fibre, was investigated. Previously developed mathematical model has been applied for the determination of the overall mass transfer coefficient based on the acceptor phase, KA, in an unsteady-state LPME

HEADSPACE VOLATILES OF CHAEROPHYLLUM AUREUM L.

Differences in the headspace volatile profiles (HS) of fresh and air-dried fruits, stems and aerial parts of Chaerophyllum aureum L. (Apiaceae) were studied here for the first time using HS-GC-MS (head space – gas chromatography – mass spectrometry). This was done in order to probe to which level HS volatiles of different plant organs were susceptible to air drying. The most dominant headspace volatiles of all samples were monoterpene hydrocarbons. Sabinene was the major volatile of the fresh aerial parts, air-dried fruits, fresh and air-dried stems, representing 47.8%, 31.4%, 67.7% and 73.0% of the total volatiles, respectively. The most abundant headspace volatiles of the fresh fruits were terpinolene (45.3%), γ-terpinene (13.1%) and β-pinene (10.2%). The air-dried aerial parts were characterized by a high amount of limonene (69.0%). The results of HS-GC-MS were subjected to multivariate statistical analysis in order to get a better insight into the similarities/dissimilarities existing between the investigated samples. According to the results of multivariate analysis, the drying process significantly influenced HS volatiles. ISPARLJIVI SASTOJCI BILJNE VRSTE CHAEROPHYLLUM AUREUM L.U ovom radu su, po prvi put, ispitane razlike u headspace profilima (HS) svežih i na vazduhu sušenih plodova, stabljika i nadzemnih delova biljne vrste Chaerophyllum aureum L (Apiaceae) pomoću metode HS-GC-MS (headspace – gasna hromatografija – masena spektrometrija). Na osnovu ovih rezultata moglo bi se utvrditi do koliko intenzivnih promena u HS profilima različitih delova biljke može doći usled sušenja biljnog materijala. U svim uzorcima su dominantni headspace isparljivi sastojci bili monoterpeni. Utvrđeno je da je sabinen bio glavni isparljivi sastojak svežeg nadzemnog dela (47,8%), suvog ploda (31,4%), svežeg (67,7%) i suvog stabla (73,0%). Kao glavni isparljivi sastojci svežeg ploda nađeni su terpinolen (45,3%), γ-terpinen (13,1%) i β-pinen (10,2%), dok je suvi nadzemni deo bio okarakterisan značajno većom zastupljenošću limonena (69,0%). Rezultati HS-GC-MS analize su podvrgnuti multivarijantnoj statističkoj analizi kako bi se dobio bolji uvid u sličnosti/razlike među razmatranim uzorcima. Na osnovu rezultata multivarijantne analize sledi da sušenje u velikoj meri utiče na HS profil. HIGHLIGHTSHeadspace (HS) profiles (percentage compositions) of different parts of Chaerophyllum aureum L. were subjected to multivariate statistical analysis.In all samples, fresh and dry, the most dominant headspace volatiles were monoterpene hydrocarbons.Sabinene was the most abundant volatile of the fresh aerial parts, air-dried fruits, fresh and air-dried stems.The main headspace volatile compound of the fresh fruits was terpinolene while limonene was the major volatile of the air-dried aerial parts