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Item Robust Co(II)-Based Metal-Organic Framework for the Efficient Uptake and Selective Detection of SO2(ACS Publications (American Chemical Society), 2024-03-26) López-Cervantes VB; López-Olvera A; Obeso JL; Torres IK; Martínez-Ahumada E; Carmona-Monroy P; Sánchez-González E; Solís-Ibarra D; Lima E; Jangodaz E; Babarao R; Ibarra LA; Telfer SGMUF-16 is a porous metal-organic framework comprising cobalt(II) ions and 5-aminoisophthalate ligands. Here, we measured its reversible SO2 adsorption-desorption isotherm around room temperature and up to 1 bar and observed a high capacity for SO2 (2.2 mmol g-1 at 298 K and 1 bar). The uptake of SO2 was characterized by Fourier transform infrared (FT-IR) spectroscopy, which indicated hydrogen bonding between the SO2 guest molecules and amino functional groups of the framework. The location and packing of the SO2 molecules were confirmed by computational studies, namely, density functional theory (DFT) calculations of the strongest adsorption site and grand canonical Monte Carlo (GCMC) simulations of the adsorption isotherm. Furthermore, MUF-16 showed a remarkable selective fluorescence response to SO2 compared to other gases (CO2, NO2, N2, O2, CH4, and water vapor). The possible fluorescence mechanism was determined by using time-resolved photoluminescence. Also, the limit of detection (LOD) was calculated to be 1.26 mM (∼80.72 ppm) in a tetrahydrofuran (THF) solution of SO2Item How Reproducible are Surface Areas Calculated from the BET Equation?(Wiley-VCH GmbH, 2022-05-23) Osterrieth JWM; Rampersad J; Madden D; Rampal N; Skoric L; Connolly B; Allendorf MD; Stavila V; Snider JL; Ameloot R; Marreiros J; Ania C; Azevedo D; Vilarrasa-Garcia E; Santos BF; Bu X-H; Chang Z; Bunzen H; Champness NR; Griffin SL; Chen B; Lin R-B; Coasne B; Cohen S; Moreton JC; Colón YJ; Chen L; Clowes R; Coudert F-X; Cui Y; Hou B; D'Alessandro DM; Doheny PW; Dincă M; Sun C; Doonan C; Huxley MT; Evans JD; Falcaro P; Ricco R; Farha O; Idrees KB; Islamoglu T; Feng P; Yang H; Forgan RS; Bara D; Furukawa S; Sanchez E; Gascon J; Telalović S; Ghosh SK; Mukherjee S; Hill MR; Sadiq MM; Horcajada P; Salcedo-Abraira P; Kaneko K; Kukobat R; Kenvin J; Keskin S; Kitagawa S; Otake K-I; Lively RP; DeWitt SJA; Llewellyn P; Lotsch BV; Emmerling ST; Pütz AM; Martí-Gastaldo C; Padial NM; García-Martínez J; Linares N; Maspoch D; Suárez Del Pino JA; Moghadam P; Oktavian R; Morris RE; Wheatley PS; Navarro J; Petit C; Danaci D; Rosseinsky MJ; Katsoulidis AP; Schröder M; Han X; Yang S; Serre C; Mouchaham G; Sholl DS; Thyagarajan R; Siderius D; Snurr RQ; Goncalves RB; Telfer S; Lee SJ; Ting VP; Rowlandson JL; Uemura T; Iiyuka T; van der Veen MA; Rega D; Van Speybroeck V; Rogge SMJ; Lamaire A; Walton KS; Bingel LW; Wuttke S; Andreo J; Yaghi O; Zhang B; Yavuz CT; Nguyen TS; Zamora F; Montoro C; Zhou H; Kirchon A; Fairen-Jimenez DPorosity and surface area analysis play a prominent role in modern materials science. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory, which has been a remarkably successful contribution to the field of materials science. The BET method was developed in the 1930s for open surfaces but is now the most widely used metric for the estimation of surface areas of micro- and mesoporous materials. Despite its widespread use, the calculation of BET surface areas causes a spread in reported areas, resulting in reproducibility problems in both academia and industry. To prove this, for this analysis, 18 already-measured raw adsorption isotherms were provided to sixty-one labs, who were asked to calculate the corresponding BET areas. This round-robin exercise resulted in a wide range of values. Here, the reproducibility of BET area determination from identical isotherms is demonstrated to be a largely ignored issue, raising critical concerns over the reliability of reported BET areas. To solve this major issue, a new computational approach to accurately and systematically determine the BET area of nanoporous materials is developed. The software, called "BET surface identification" (BETSI), expands on the well-known Rouquerol criteria and makes an unambiguous BET area assignment possible.Item Comparison of Cd(II) adsorption properties onto cellulose, hemicellulose and lignin extracted from rice bran(Elsevier Ltd, 2021-06) Wu C; Ren M; Zhang X; Li C; Li T; Yang Z; Chen Z; Wang LRice bran, an underutilized by-product obtained from outer rice layers, has received wide interest due to its abundance, eco-friendliness, and low cost. In this research, cellulose, hemicellulose and lignin as the main components of rice bran were fractionated, and their Cd(II) adsorption capacity, behavior and mechanism were further studied. The adsorption capacity of cellulose for Cd(II) was 5.79 mg/g within the equilibrium time of 10 min, which was 1.8 and 3.6 times those of hemicellulose and lignin, respectively. The Cd(II) adsorption onto cellulose exhibited monolayer surface behavior, whilst the heterogeneous adsorption behavior was observed for hemicellulose and lignin. These differences were related to the discrepancy of morphology and chemical composition in three polymers. The multi-hole sticks morphology of cellulose and porous blocky structure of hemicellulose were observed, while lignin showed compact and agglomerated blocky structure. Cellulose had numerous available adsorption sites including the oxygen-containing functional groups, which bonded with Cd(II) driven by chemical interaction. In conclusion, it highlights that cellulose from rice bran has the great potential of being applied as adsorbent for the Cd(II) removal.Item In situ recovery of secondary metabolites using adsorption resins : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy at Massey University, Palmerston North, New Zealand(Massey University, 2006) Ryan, Jason L. JAlmost without exception a two to three fold increase in microbial secondary metabolite concentration was measured when adsorption resins were added in-situ during a submerged liquid fermentation. Anguidine was produced at a final concentration of 440 mg/L after five days in a shake flask that contained adsorption resin, compared to 300 mg/L without resin. Rapamcyin was produced at a final concentration of 87 mg/L after six days in a shake flask that had resin present, compared to 28 mg/L without resin. Ansamitocin P3 was produced at a final concentration of 24 mg/L after six days in a shake flask with resin, compared to 9.75 mg/L without resin. The increase in secondary metabolite concentration confirmed that the resins used provided a positive influence on secondary metabolite production. Adsorption resins for shake flask studies were selected based on their ability to achieve maximum adsorption of specific secondary metabolites in various fermentation systems. A library of adsorbed concentrations was collected for the three secondary metabolites studied. The lipophilicty of the metabolite, calculated by several software packages, was compared to the polarity of the adsorption resin to generate a relationship. By using the preceding set of data it is possible to select adsorption resins that improved the produced concentrations of the target organic secondary metabolites. The fermentation media compositions tested appeared to have no effect on the final product concentration when adsorption resins were added in situ during the fermentations. Based on the lipohilictiy of the secondary metabolite and the polarity of the resins, it is possible to select a resin that achieves a high adsorption concentration of the target organic secondary metabolite.Item The adsorption of adsorbable organic halide onto biological solids : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Technology in Environmental Engineering(Massey University, 1994) Gapes, Daniel JamesChlorinated organic molecules may be removed from wastewaters by adsorption onto the biomass present in biological treatment systems. This study assessed the adsorption onto biological solids of Adsorbable Organic Halide (AOX) from two New Zealand kraft pulp and paper mill bleach plant wastewaters. Batch adsorption studies were carried out to determine the characteristics of this adsorption process, with activated sludge as an adsorbent. Different molecular weight AOX fractions from two bleach plants' wastewaters were studied. The first wastewater was a combined C and E stage effluent from the CEH bleach sequence previously used at the Tasman Pulp and Paper Co. Ltd, Kawerau. The second was a combined D and E o stage effluent from the OODEoD bleach sequence used at New Zealand Forest Products Kinleith Mill, Tokoroa. For each mill's wastewater, the adsorption isotherms were characterised for four different molecular weight fractions, and the unfractionated wastewater. Adsorption isotherm models used to fit the data for each of the fractions were the Freundlich, Langmuir and Irreversible isotherms. No single model was able to successfully describe the adsorption characteristics for all of the fractions analysed, indicating significant differences in the adsorption processes occurring in the various fractions. Analysis of the adsorption of the different molecular weight fractions demonstrated that the adsorption affinity of the AOX increased with increasing molecular weight. It appeared that molecules with higher chlorination levels were more effectively adsorbed onto the biomass. Competition for adsorption sites on the biomass by the different molecular weight fractions was a significant factor in the adsorption of the unfractionated wastewater. Analysis of the adsorption of AOX from the wastewaters at concentrations typical of those expected in different biological treatment systems showed that: • treatment systems with low biomass concentrations, such as aerated lagoons, would not be expected to remove significant amounts of AOX by adsorption. • treatment systems utilising higher biomass levels have the potential to remove significant amounts of AOX by adsorption. Conventional activated sludge systems could remove 15-20%, and oxygen activated sludge systems 25-50% of the AOX entering these systems. The impact of the modernisation of bleach sequences on the adsorption of AOX, by the introduction of oxygen delignification and chlorine dioxide substitution, was assessed. This was carried out by comparison of the adsorption characteristics of the two mills' wastewaters. The Tasman mill's bleach sequence was used as an example of older, conventional bleaching, and the Kinleith mill's sequence an example of modernised bleaching. Significant differences were found in the adsorptive behaviour of the molecular weight fractions, and that of the unfractionated wastewaters, between the two. From the analysis, adsorption onto biomass in a biological treatment system is predicted to alter the molecular weight distribution of the AOX in wastewaters. The conventional sequence's wastewater should show a decrease in the proportion of high molecular weight AOX due to this adsorptive removal, an effect not as significant in the adsorption of AOX from a modern bleach plant wastewater. Modern bleach sequence wastewaters are expected to reveal a decrease in the proportion of the low molecular weight material, an effect not as notable for the conventional sequence's AOX. Modernisation was found to decrease the adsorptive affinity of the wastewater, suggested to be due to the lower chlorination levels and average molecular weights of the molecules in the wastewater. It was concluded that the modernisation of bleach sequences has reduced the significance of adsorption onto biological solids as an AOX removal mechanismItem Diffusion and uptake of moisture through paint films leading to corrosion of metal substrates : a diffusion-adsorption model with reaction : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mathematics at Massey University(Massey University, 1996) Van Dyke, Antony K.Corrosion occurs in response to the availability of water, oxygen and other agents at metal surfaces. The rate of corrosion depends critically upon the concentrations of these agents. At a metal surface protected by a paint layer, these concentrations are governed by diffusion through the paint film and by adsorption onto the metal surface in competition with polymer molecules of the adherent paint film. A mathematical model is developed for this problem and its behaviour and evolution in time is analysed. The conceptual basis of this model is different from others in that it combines equations of diffusive processes with equations of paint film adherence (competitive adsorption) at the metal surface. The corrosion process is considered to arise through boundary conditions for the diffusion equations with rates governed by variables described in the competitive adsorption equations. The nonlinearity of these competitive adsorption equations is the key to describing long periods of protective action provided by paint films, with negligible corrosion of the metal substrate, followed by the sudden onset of rapidly accelerating corrosion and the consequent accumulation of corrosion product (rust). Concomitant loss of competitive adsorption (adhesion) by the paint film is a typical end result. Electrochemical activity of the metal substrate is evaluated as a corrosion current. This is determined by concentrations of water and oxygen in the internal environment, and by chemical activity in the adsorbed layer. The mechanism of corrosion of a painted metal surface is theorised to occur through active sites not covered by adsorbed polymer, water or oxygen. Numerical simulations were done using a detailed computer algorithm developed specifically for this purpose. These simulations give insight into the model's behaviour and aid determination of simplified constitutive relationships which lead to a simplified model which allows easy determination of the thresholds for the onset of rapid corrosion. It turns out that the diffusion of water and oxygen through the paint film is normally very quick. The rate determining step is directly related to the competition between water, oxygen and coating polymer adherent to the metal surface, and coating polymer adherent to corrosion product. Once zinc (or any other metal) ions approach saturation in solution at the metal surface, the coating polymer approaches saturation with zinc and loses competitive adsorption onto the metal surface. Crystallinity of the adsorbed polymer declines and chemical activity coefficients in the adsorbed layer are reduced. Concentrations of water and oxygen in the adsorbed layer increase and metal active sites are exposed. The result is a surge in the rate of corrosion leading to the rapid formation of corrosion product. This in turn leads to enhanced degradation and free corrosion of the metal surface.Item Ab initio calculations of water and ice : structural, electronic and optical properties : a thesis submitted in partial fulfillment of the requirements of the degree of Doctor of Philosophy at Massey University, Albany, New Zealand(Massey University, 2009) Hermann, AndreasExtended aqueous systems, crystalline ice and liquid water, are studied computationally to investigate their ground state and excited state properties. Methods from solid state physics and quantum chemistry are combined to shed light on some of the unusual properties of water and ice. For the ground state of crystalline ice, density functional theory (DFT) calculations are compared to an ab initio incremental ansatz that utilizes periodic Hartree-Fock together with localized electron correlation calculations. It is shown that the many-body decomposition of the electron correlation converges very fast, allowing the achievement of excellent agreement with experimental data even when limiting correlation energy contributions to two-body terms only. The incremental method is utilized by a computer program that combines the periodic and localized calculations, and allows for structural optimization of the system of interest. The adsorption of water molecules on the surface of ice is studied using DFT. Adsorption is found to be favoured on non-crystallographic adsorption sites, and a slight tendency towards the formation of rough surfaces is reported. The localization of excess electrons at the surface of ice is facilitated by coadsorbed water molecules. For a correct theoretical description of the latter, a self-interaction correction scheme for the excess electron has to be used. However, it is sufficient to limit the self-interaction correction to the excess electron only, since the neutral ice surface itself is well described within conventional DFT. The self-interaction correction scheme is incorporated into a commonly used DFT program package. Optical excitations of crystalline ice are calculated using many-body perturbation theory. Solving the two-particle Bethe-Salpeter equation yields optical spectra in excellent agreement with experimental data. Based on this agreement, an embedding model is developed that reduces the hydrogen bond network to its most important contribution. The model is applied to crystalline ice, where it reproduces the experimental spectral features, and to microscopic liquid water structures obtained from molecular dynamics simulations, where it reproduces the energy shift of the first absorption peak and gives overall good agreement with experiment. The driving force of water’s anomalous optical behaviour is identified.Item Effects of milk protein ingredients on physico-chemical properties of rice starch : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University Palmerston North, New Zealand(Massey University, 2009) Noisuwan, AngkanaThe overall aim of this thesis is to determine if the interactions between normal and waxy rice starch and milk proteins from four milk protein ingredients, namely skim milk powder (SMP), milk protein concentrate (MPC), sodium caseinate (NaCAS) and whey protein isolate (WPI) do occur, and to identify the mechanisms underlying these interactions. Different milk protein ingredients at various concentrations (0 to 10%, w/w) affected markedly and differently the pasting behaviour of 10% (w/w) rice starches. SMP delayed the pasting of both rice starches by increasing the onset temperature (Tonset) and the peak viscosity temperature (Tpeak) of pasting. This was mainly due to the presence of lactose and ions, which was further supported by the investigation of the effects of UFSMP (a solution of salts and lactose present in SMP at their proper concentration) and lactose. The addition of NaCAS also delayed the pasting of rice starch; Tpeak in the case of both starches was increased. For normal rice starch paste, MPC and WPI decreased the Tpeak. MPC had no affect on Tpeak of waxy rice starch paste. The qualitative viscoelastic behaviour of rice starch/milk protein ingredient gels obtained from the above pastes was dominated by the continuous phase made of the starch molecules. There was evidence, as indicated by confocal microscopy, of phase separation between the milk proteins of SMP and MPC and the two starches. The phase separation was not observed in the addition of either NaCAS or WPI. Studies on the thermal behaviour of rice starch/milk protein ingredient mixtures by differential scanning calorimetry (DSC) showed that SMP, similarly to UFSMP, delayed the gelatinization of both starches. NaCAS also delayed the gelatinisation of both starches but had a greater effect on waxy than normal rice starch. The addition of NaCAS did not affect Tonset but increased Tpeak for normal rice starch, whereas the gelatinisation temperature of waxy rice starch was highly affected by the addition of NaCAS with both Tonset and Tpeak shifted to higher temperatures. MPC had no affect on the gelatinization temperature of normal rice starch, whereas the gelatinization temperature of waxy rice starch was increased by the addition of MPC. The addition of WPI to both rice starches showed two thermal transitions. The first of these was due to the gelatinisation of the starches and the second to the denaturation of ß-lactoglobulin (ß-lg). The addition of WPI to normal rice starch showed that the thermal behaviour of normal starch and protein were independent from each other. In contrast, the thermal behaviour of waxy rice starch was modified by the addition of WPI; both Tonset and Tpeak were increased. SMP decreased the Tonset of swelling, swelling ratio and the amount of starch leaching from both starches. These observed changes were due to the presence of lactose and ions in SMP. NaCAS slightly increased Tonset of swelling but the amount of starch leaching was reduced for both rice starches. The rigidity of both starches tended to increase in the presence of NaCAS. MPC and WPI affected the swelling behaviour of normal and waxy rice starch differently. A dramatic increase in the swelling of normal rice starch/MPC or WPI mixtures was observed, whereas this trend was not evident for waxy rice starch/ MPC or WPI mixtures. The difference in the water holding ability and gelatinization peak temperatures of the two starches over the temperature range at which whey proteins denature and form gels are believed to be responsible for the observed differences. The results from confocal microscopy showed that milk proteins, such as a-casein, ß- casein, ß-lg and a-lactalbumin (a-la), were adsorbed onto the granule surface of both normal and waxy rice starch. The mechanism for this adsorption is the hydrophilic interactions; hydrogen bonds between hydroxyl group from terminated glucan molecule that protrude around starch granule surface-hydroxyl; amino, or other electron-donation or electron-accepting groups of the added proteins. Using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) it was found that for SMP and MPC the adsorbed as- to ß-casein ratio on both starches was similar to the as-casein to ß- casein ratio in the casein micelle at low SMP and MPC concentrations. But at high concentrations of SMP or MPC, this ratio decreased indicating that more ß-casein was adsorbed preferentially to as-casein. In the case of NaCAS, as-casein was adsorbed preferentially to ß-casein. Moreover, there was evidence of multilayer adsorption of ascasein into the surface of rice starch granules. Compared to the other milk protein ingredients, very small amounts of the ß-lg and a-la from WPI were adsorbed onto starch granules. However, the adsorbed amounts of ß-lg and a-la from WPI continuously increased with increasing WPI concentration, suggesting that these two proteins, particularly ß-lg, adsorbed in multilayers too.