Jacek Wiśniewski

Water and acid recovery from the rinse after metal etching operations

Abstract The effluent from which water and acid were to be recovered came from the rinse after metal etching with hydrochloric acid. The effluent under study contained hydrochloric acid (24 eq H + /m 3 ), iron salts (100 g Fe tot /m 3 ), small amounts of nickel salts (2.7 g Ni 2+ /m 3 ) and chromium salts (0.6 g Cr 3+ ), and had an electrolytic conductivity of 8.4 mS/cm. Water recovery was investigated using two alternative treatment trains: electrodialysis 1 (ED1)+cation exchange+electrodialysis 2 (ED2), and cation exchange+ED1+ED2 (referred to as systems 1 and 2, respectively). System 1 yielded acid-free water which contained only trace amounts of ballast substances (metal salts) and had a conductivity of 30 μS/cm. System 2 provided water without acid and metal salts, and had a conductivity of 3 μS/cm. The acid and metal salt concentrate produced in the course of ED1 was subjected to monoselective electrodialysis (ED mon ) for recovery and further concentration of hydrochloric acid. The composition of the concentrate obtained from the electrodialysis of raw wastewater (system 1) showed a lower content of acid and a higher content of iron salts (260 eq H + /m 3 and 850 g Fe tot /m 3 , respectively) than the concentrate produced by the electrodialysis of wastewater with cation exchange as a prior step (system 2; 410 eq H + /m 3 and 48 g Fe tot /m 3 , respectively). As a result, the acid solution recovered by ED mon in system 2 was more concentrated than that of system 1. Acid enrichment related to that of the raw wastewater was 74 times as high. The calculated cost of water and acid production in systems 1 and 2 amounts to 0.4 DEM/m 3 of water and 1.55 DEM/m 3 of water, respectively. It should be stressed, however, that the lower production cost in system 1 implies a noticeable poorer quality both for the recovered water and for the recovered hydrochloric acid solution.

Age dependent changes in the binding and hydrolysis of juvenile hormone in the haemolymph of last instar larvae of Galleria mellonella

Abstract Binding and hydrolysis of juvenile hormone I (JH) and cleavage of four 1-naphthyl esters were determined in the haemolymph of Galleria mellonella throughout the last larval instar. JH binding per ml haemolymph parallels changes in the protein content with a maximum at the onset of spinning at 120 hr (152 mg protein/ml; binding of 20 n-mole JH/ml) and a drop at the pupal ecdysis. Activity of JH esterase(s) exhibits two maxima: first between cessation of feeding and the start of spinning at 96–120 hr (hydrolysis of 65 n-mole JH/ml/min) and second just before pupal ecdysis at 168 hr (52 n-mole JH/ml/min). Correlations between these changes and available data on the JH content in caterpillars indicate that JH binding protein and JH esterase(s) may play a role in clearing JH from its target tissues rather than in regulating its amounts. Fluctuations in the hydrolysis of 1-naphthyl esters of acetate (max. 4.5 μ-mole/ml/min), butyrate (max. 21 μ-mole/ml/min), palmitate (max. 0.5 μ-mole/ml/min), and laurate (max. 0.4 μ-mole/ml/min) reflect primarily the feeding activity of caterpillars and follow a very different course than changes in the potential to hydrolyze JH.

Biosynthesis and degradation of juvenile hormone in corpora allata and imaginal wing discs of Galleria mellonella (L.)

Abstract The rate of juvenile hormone (JH) biosynthesis by corpora allata-corpora cardiaca complex (CA/CC) during two last larval instars of Galleria mellonella was analysed. The rate of biosynthesis reaches maxima at the beginning of the VIth and VIIth instars. It is markedly reduced before the last larval ecdysis and after the first day of the last larval instar. After passing the second day of the last larval instar CA/CC exhibits again an increased ability for the biosynthesis of JH. The JH esterase activity in CA/CC is very low at the beginning of last larval instar and rapidly increases after the first day of this instar. Beginning on the second day of last larval instar the rate of JH hydrolysis is always higher than the rate of JH synthesis in CA/CC. It is concluded that the secretion of JH by CA/CC is possible until the second day of the last larval instar. After this, JH-acid can be supplied by CA/CC to peripheral tissues. The imaginal wing discs of mobile prepupa exhibit the ability to methylate JH-acid. It is concluded that some elevations of JH titre in G. mellonella haemolymph after the second day of VIIth instar are due in part to JH-acid methyltransferase activity in the imaginal discs.

Tissue specific juvenile hormone degradation in Galleria mellonella

Degradation of juvenile hormone III (JH III) in the fat body integument and silk glands of the last instar larvae of Galleria mellonella follows two major routes: the ester bond hydrolysis and the epoxide ring hydration. The juvenile hormone esterase activity is primarily localized in the cytosol as a 70–100 kDa protein fraction with an isoelectric point of pH 4.7. The epoxide hydrolase activity was found both in the 100,000 g supernatant and in the insoluble cell fraction. The soluble epoxide hydrolase occurs in the form of “an aggregated protein” of a molecular weight over 1000 kDa. On the first day of the last larval instar, the epoxide hydrolase activity accounts for approx. 50, 80 and 90% of JH III degradation in the fat body, integument and silk glands respectively. This activity is present both in the cytosol and in the insoluble cell fraction. The importance of the esterase activity for JH III degradation increases in the course of the instar. In the fat body it becomes dominant already on day 2, when the epoxide hydrolase activity completely disappears from the cytosol. The ester cleavage also becomes the major route of JH degradation in the integument from day 4, but in the silk glands it becomes equal to the rate of epoxide hydration only on day 6. In contrast to these tissues, JH III degradation in the haemolymph occurs only via esterolytic cleavage.

Juvenile hormone binding proteins from the epidermis of Galleria mellonella

Abstract Juvenile hormone binding proteins (JHBP) have been detected in cytosol of larval and pupal epidermis of Galleria mellonella. Juvenile hormone (JH) binding activity changes during insect development, reaching a maximum after each ecdysis. Using density gradient centrifugation, three distinct peaks of JHBP have been detected: 8.8–9.2 S, 4.2–4.6 S, and 3 S. Despite molecular mass heterogeneity of the JHBPs, only one class of JH binding sites has been detected. The equilibrium dissociation constants (Kd) of the larval JHBP for the natural (10 R, 11 S) JHs and their enantiomers are: Kd, (10 R, 11 S)-JH I = 24 ± 9 nM; Kd, (10 S, 11 R)-JH I = 51 ± 15 nM; Kd, (10 R, 11 S)-JH II = 9.7 ± 2.0 nM, Kd, (10 S, 11 R)-JH II = 18 ± 3 nM. From competitive binding assays using 3H-labeled (10 R, 11 S)-JH II, it was found that racemic JH III and the JH analog (10 R, 11 S)-12-iodo-JH I are bound with affinity close to the unnatural (10 S, 11 R) enantiomer of JH I. Juvenoid R 394 (a methoprene analog) is bound to JHBP with an affinity 100-fold lower than (10 R, 11 S)-JH II, whereas binding of the epoxygeranylphenyl ether juvenoid R 20458 is not detectable. Addition of 0.1% (w/v) Zwittergent 3–10 to the epidermal cytosol causes an increase of JH binding activity by 2–10-fold in penultimate and ultimate instars, respectively. This zwitterionic N-alkyl sulfobetaine detergent apparently converts a high molecular mass JHBP species into a 65-kDa component, but does not change the stereospecificity or the affinity of JHBP towards the JH homologs or analogs.

Juvenile hormone degradation in brain and corpora cardiaca-corpora allata complex during the last larval instar ofGalleria mellonela (Lepidoptera, Pyralidae)

Time course analysis of juvenile hormone degradation in the brain and the corpora cardiaca-corpora allata complex shows that during the first two days of the last larval instar the juvenile hormone degradation is very low. Starting from the third day up to the seventh day a continuous increase of esterase activity is observed.

Recovery of acid and water by membrane dialysis

Abstract The processes of electrodialysis and diffusion dialysis were tested to recover water and acid from model solutions containing hydrochloric acid and ferric ions. The electrodialysis process was run with domestic ion-exchange membranes of AESD-2a and KESD-2 type. Dialysis was conducted with anion-selective Selemion AMV (Asahi Glass) membranes. Electrodialysis yielded acid removal of 93 to 96% at current densities ranging from 100 to 300 A/m2 and an energy consumption approaching 50 Wh/val H+. Diffusion dialysis provided acid removal of 56 to 67% and 38 to 46% at a volume of ratios of 4/40 and 4/6, respectively. The experiments were carried out for 10 days. The retention of ferric ions was very high throughout amounting to 98–99%.

Removal of bromide ions from an aqueous solution by Donnan dialysis with anion-exchange membranes

Abstract The potential of Donnan dialysis to remove the bromide ions and associated ions (nitrates and bicarbonates) from a model solution was examined, using three anion-exchange membranes (AMEs) differing in their ion-exchange capacity and water content: Selemion AMV, Neosepta AFN and Neosepta ACS. Selemion AMV provided the most advantageous exchange of bromide ions for chloride ions and effectively limited co-ion transport, thus contributing to the lowest salt leakage into the feed observed in this study. The efficiency of bromide exchange ranged from 70 to 78% (for 500 μg Br−/L) at a salt concentration in the receiver of 100 and 300 mM NaCl, respectively. Anion exchange with Neosepta AFN (characterized by a loose structure) proceeded at a faster rate and provided a slightly lower efficiency of bromide removal (68–70%). The a major advantage that Neosepta AFN offered was the short duration of the process (the time required for achieving minimal bromide concentration in the feed). Nonetheless, the loose...

Decolorization of Dye Solutions by New Tubular Polysulfone Membranes

Abstract Polysulfone membranes were prepared from 12.5, 13.75, and 15% (wt. %) polysulfone solution in dimethylformamide and formed on the surface of porous, sintered polymethyl methaerylate bars. An effective surface of each membrane was 49.2 cm 2 . The effect of some casting parameters (composition and the temperature of the casting solution, time of solvent evaporation) and the pressure applied on the transport and separation properties of the membranes were analyzed. The experiments were carried out in a 1.2 dm 3 pressure apparatus with continuous circulation of the permeate between feeding tank and the apparatus. It was found that membranes cast from 12.5% polysulfone solution of a temperature of 298 K with no solvent evaporation displayed the best properties. After 160 hours of operation at 0.18 MPa, the membranes in question showed an ability of a 97 to 99% rejection of 781.2 molecular-weight dye. The volume flux of the dye solution varied from 0.6 to 0.8 m 3 /m 2 per day.

Assessing the utility of some technological trains for water recovery from acid and metal salt solutions

Abstract Studies on high-quality water recovery from mineral acid (HCl, H2SO4, HNO3/HF) and iron salt solutions were presented. Water was recovered via three treatment trains involving electrodialysis (ED) and cation exchange in various combinations: System 1: ED1+ED2; System 2: ED1+cation exchange+ED2; and System 3: cation exchange+ED1+ED2. Water recovered via System 3 displayed the highest quality: its conductivity varied from 2 μS/cm (recovery from HCl solution) to 49 μS/cm (recovery from H2SO4 solution). It was found, however, that pre-decationization raised the deionized water consumption for the rinsing of the ion exchanger, thus decreasing the efficiency of water recovery as compared to System 1 or System 2. That is why, the cost of water recovery via System 3 is relatively high. Water can be also recovered via System 1 or System 2. System 2 provided water of slightly better parameters: water contained trace amount of iron salt and its conductivity varied from 4 μS/cm (water from HCl solution) to 61 μS/cm (water from H2SO4 solution). The calculated cost of water production via System 2 is almost the same as that in System 1.