STUDY OF THE CONTAMINATING MICROBIOTA OF OLD PAPER SUPPORTS

Biodeterioration has drawn the attention of different specialists who started to cooperate and to understand the need of joint research to have a picture as comprehensive as possible of the degradation agents and the measures that can be taken to salvage the heritage assets. This paper contains a description of the microbiota identified in two types of old paper supports part of a private collection from North Moldavia (Romania), namely a church book from the end of the 19th century for which the paper was obtained manually from textile fibres, and a book from 1870 with paper from cellulose pulp derived from wood. To the purpose of identifying the types of bacteria and fungi present on the supports examined, several comments were made related to the morphology of the colonies developed on the growth medium, which provided important indications for the determination based on the microscopical examination as well. Bacterial contamination (of the genera Bacillus, Clostridium, Pseudomonas and Micrococcus) was detected in most samples collected. The diversity of the fungi isolated from the paper supports (the genera Penicillium, Alternaria) is the result of the fact that since they are highly hygroscopic materials, they have the capability to retain water more easily, which stimulates fungal growth. The investigations made to determine the presence of microorganisms responsible for degradation and their identification allowed the discovery and acertainment of the real and justified need to find ways to prevent biodeterioration or to inactivate and destroy biodeteriogens by non-invasive, eco-friendly chemical and physical treatments

Reduction of Water Color in a Spinning Disc Reactor

In this study, spinning disc (SD) technology was successfully applied to a synthetic water to remove its color. The preliminary data performed in a regular mixing system using a potential adsorptive material, i.e., double-layered hydroxide of a ZnAlLDH type, did not provide a significant decrease (no more than 10–15%) in the water color content. Thus, ZnAlLDH (2 g/L) was added to the synthetic water containing 50 mg/L Rosso Remazol RB dye that was subsequently fed onto the spinning disc. The SD efficiency was investigated at four different water-supplying flow rates (5.76, 6.00, 7.44 and 8.16 L/h) and four different disc rotational speeds (100, 250, 500 and 800 rpm). The best color removals of 44.39%, 41.14% and 42.70% were obtained at 6 L/h and 250 rpm, 6 L/h and 500 rpm and 5.76 L/min and 800 rpm, respectively, in only a 50 min working time period. In addition, for a relatively low color concentration in water (~30 mg/L dye) and at the lowest electric power consumption, Fenton oxidation was performed in the SD setup for a more advanced color removal of 62.54% within a 50 min time period. Furthermore, two other materials, titanium and aluminium oxides, underwent similar investigations in the SDR setup, and the obtained results were comparatively discussed. The FTIR spectra of each solid material before and after the SD technology application were used to appreciate the dye-retention performance of each material used. The obtained results indicated that the spinning disc technology correlated with the tested materials could significantly improve the water color (over 40% color reduction), this level of color reduction being higher than that obtained following a coagulation–flocculation test (20–28% color reduction), an ion exchange (25–30% color removal) or a sand filtration step (15–20%) applied to the same dye-based water sample. A further increase in color removal could be achieved by using an additional oxidative step (more than 65% color reduction)

Reduction of Water Color in a Spinning Disc Reactor

In this study, spinning disc (SD) technology was successfully applied to a synthetic water to remove its color. The preliminary data performed in a regular mixing system using a potential adsorptive material, i.e., double-layered hydroxide of a ZnAlLDH type, did not provide a significant decrease (no more than 10–15%) in the water color content. Thus, ZnAlLDH (2 g/L) was added to the synthetic water containing 50 mg/L Rosso Remazol RB dye that was subsequently fed onto the spinning disc. The SD efficiency was investigated at four different water-supplying flow rates (5.76, 6.00, 7.44 and 8.16 L/h) and four different disc rotational speeds (100, 250, 500 and 800 rpm). The best color removals of 44.39%, 41.14% and 42.70% were obtained at 6 L/h and 250 rpm, 6 L/h and 500 rpm and 5.76 L/min and 800 rpm, respectively, in only a 50 min working time period. In addition, for a relatively low color concentration in water (~30 mg/L dye) and at the lowest electric power consumption, Fenton oxidation was performed in the SD setup for a more advanced color removal of 62.54% within a 50 min time period. Furthermore, two other materials, titanium and aluminium oxides, underwent similar investigations in the SDR setup, and the obtained results were comparatively discussed. The FTIR spectra of each solid material before and after the SD technology application were used to appreciate the dye-retention performance of each material used. The obtained results indicated that the spinning disc technology correlated with the tested materials could significantly improve the water color (over 40% color reduction), this level of color reduction being higher than that obtained following a coagulation–flocculation test (20–28% color reduction), an ion exchange (25–30% color removal) or a sand filtration step (15–20%) applied to the same dye-based water sample. A further increase in color removal could be achieved by using an additional oxidative step (more than 65% color reduction)

Computational Study of Some 4’-Aryl-1,2,4-triazol-1-ium-4-R₂-phenacylid Derivatives in Vacuum and Dimethylformamide

Four carbanion monosubstituted 4’-aryl-1,2,4-triazol-1-ium-4-R2-phenacylids, used as precursors in obtaining new heterocyclic compounds, and their corresponding derivatives belonging to the C2v point group of symmetry were studied by computational means in dimethylformamide (DMF) solutions compared with their isolated state. The changes in the computed parameters induced by the solvent compared with those of the isolated molecules were analyzed in this paper. The charge distribution and the molecular energies in the HOMO and LUMO, the electronic states responsible for the visible absorption band of 4’-aryl-1,2,4-triazol-1-ium-4-R2-phenacylids, in their isolated state and in solutions achieved in DMF were computed and compared with the visible electronic absorption spectra. The molecular descriptors of the studied compounds were computed, and the higher reactivity of the carbanion monosubstituted 4’-aryl-1,2,4-triazol-1-ium-4-R2-phenacylids compared with symmetric derivatives was established. The obtained results can help researchers to obtain new heterocycles with applications in the drug industry

Computational and Spectral Means for Characterizing the Intermolecular Interactions in Solutions and for Estimating Excited State Dipole Moment of Solute

The results obtained both in quantum chemical computation and in solvatochromic study of pyridinium di-carbethoxy methylid (PCCM) are correlated in order to estimate the electric dipole moment in the excited state of this molecule. This estimation is made by a variational method in the hypothesis that the molecular polarizability does not change in time of the absorption process. Ternary solutions of PCCM in protic binary solvents are used here, both establishing the contribution of each type of interaction to the spectral shift and to characterize the composition of the first solvation shell of PCCM. Results are compared with those obtained before for other binary solvents. The difference between the interaction energies in molecular pairs of PCCM-active solvent and PCCM-less active solvent was also estimated based on the cell statistical model of the ternary solutions

Synergistic effect of fuel agents and mass ratio for morpho-structural optimization of magnetic claybased nanocomposites with high adsorption capacity

International audienceThe study is focused on creating magnetic mesoporous materials through the insertion of a nickel ferrite into the structure of kaolin-type clay. Sol-gel auto-combustion method was employed to synthesize the materials, using glycine and tartaric acid as chelating/combustion agents. This is the first study on the combined effect of different fuel agents and of clay-to-ferrite molar ratio on the structural, textural, magnetic and adsorptive properties of nanocomposites. The value of the average pore size, registered in a range of 6.01 and 12.9 nm, indicates the dependence on both molar ratio and fuel agent. The textural properties of the materials, corroborated with those obtained from XRD, SEM and TEM and VSM, suggest that magnetic nanocomposites can be successfully used as adsorbents in the removal of harmful organics. The obtained nanocomposites show excellent adsorption, with up to 98% BB41 dye removal, and a facile recuperation, due to their magnetic properties. The maximum adsorption capacity of dye, of 752.2 mg/g, was obtained for C3Ni_act350, in the presence of H2O2 in solution. More than that, the adsorption capacity of magnetic composites increased with increasing the NiFe2O4 content