particles of nanometric scale are formulated from a biodegradable polymer and a drug, a modified drug delivery/drug targeting or an improved pharmacokinetic profile of the compound is feasible. Also, improvements in selectivity, protection of the drug against fast metabolism, and more effective diffusion through biological barriers may become attainable [7].ABSTRACT The aim of this study was to formulate nanoparticles from poly(l)lactide by a modified nanoprecipitation method. The main focus was to study the effect of cosolvent selection on the shape, size, formation efficiency, degree of crystallinity, x-ray diffraction (XRD) reflection pattern, and zeta potential value of the particles. Low-molecular-weight (2000 g/mol) poly(l)lactide was used as a polymer, and sodium cromoglycate was used as a drug. Acetone, ethanol, and methanol were selected as cosolvents. Optimal nanoparticles were achieved with ethanol as a cosolvent, and the formation efficiency of the particles was also higher with ethanol as compared with acetone or methanol. The particles formulated by ethanol and acetone appeared round and smooth, while with methanol they were slightly angular. When the volume of the inner phase was decreased during the nanoprecipitation process, the mean particle size was also decreased with all the solvents, but the particles were more prone to aggregate. The XRD reflection pattern and the degree of crystallinity were more dependent on the amount of the solvents in the inner phase than on the properties of the individual cosolvents. The zeta potential values of all the particle batches were slightly negative, which partially explains the increased tendency toward particle aggregation.Nanoprecipitation has been used to formulate nanoparticles by many researchers [8][9][10]. Complex hydrodynamic processes at the interfacial area lead to the creation of the nanoparticles [8,11]. Polylactide(s) have been widely used in earlier nanoparticle studies, although the low-molecular-weight fractions of polylactic acid (PLA) have been used in few studies (L. Peltonen, P. Koistinen, J. Hirvonen, unpublished data, 2002). The interest in using low-molecular-weight PLA is based on a shorter degradation time as compared with longer chain analogues: PLA of M w 2000 g/mol, with a controlled drug release lasting for a few hours, has been shown to be suitable, for example, in pulmonary sustained-release formulations [12,13].In this article, PLA nanoparticles were formulated by a modified nanoprecipitation method. The main focus was to study the effect of selected cosolvents on the size and shape and several physicochemical properties (aggregation tendency, x-ray diffraction [XRD] pattern, zeta potential) of the particles. Sodium cromoglycate, a compound used in the treatment of bronchial asthma, was used as a model drug. Chloroform was used as a solvent for the polymer, PLA (M w = 2000 g/mol). The cosolvent (acetone, ethanol, or methanol) was used as a "poor" solvent (a driving solvent) for the polymer. The function of the cosolvent was...

Magnetite (Fe3O4) is a key economically valuable component in iron ore and is extracted by dissolution processes, but among the Fe (oxyhydr)oxides its solubility behavior is one of the least understood. The objective of this study was to improve understanding of magnetite dissolution mechanisms leading to thermodynamic equilibrium by comparing the dissolution of two solid samples, one synthetic and one industrial, using oxalic, sulfuric, and nitric acids at varying concentrations and temperatures. Of the three solid-liquid systems investigated, only the system consisting of magnetite and oxalic acid reached an equilibrium state within the duration of an individual experiment (6 h). In this system, increasing the acid concentration resulted in a significant increase in the equilibrium concentration of dissolved Fe. When dissolving synthetic and industrial magnetite, increasing the temperature not only increased the rate of reaction but also affected the concentration of dissolved Fe. Significant effects were observed when increasing the temperature from 15 to 35°C, but only slight differences were seen on further increases in temperature. Observations regarding the equilibrium state of the sulfuric and nitric acid systems could not be made because equilibrium was not reached. The most important individual observation regarding the equilibrium state of the nitric- and sulfuric-acid systems seems to be that in future studies a much longer reaction time is necessary, due to slow kinetics of the dissolution mechanism. A proton-based mechanism has been hypothesized as the one governing the dissolution of magnetite by these two acids, but only the dissolution of the industrial sample yielded results that were similar for these two acids and consistent with that hypothesis.

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This work focuses on the removal of sulfate from mining waters by using electrocoagulation with iron electrodes. A comparison of the results obtained by electrocoagulation with those obtained with the application of conventional chemical coagulation is provided. The results show that sulfate can be removed from synthetic mining waters by electrocoagulation, and that the pH and coagulant dosage play a very important role. During chemical coagulation under acidic conditions, it is possible to use a low dosage of iron and remove more than 80% of the sulfate present in water. However, chemical coagulation seems to behave as a kind of ion-exchange process

A new designed sonicated, continuous modular crystallizer was investigated and developed. The concept and design criteria for the designed crystallizer were examined and studied in a cooling crystallization process with three model compounds which were K 2 SO 4 , CuSO 4 , and phthalic acid. Results showed that ultrasound had significant effects, which can enhance the nucleation and avoid clogging in the tubular crystallizer. The present work shows the obtained results when different cooling strategies were studied. Equal supersaturation throughout the crystallization process was the best solution for designing temperature profiles for the modules. In addition to the cooling strategy, the residence time is one of the key factors to get feasible operating conditions in the designed crystallizer. Higher yields were obtained using ultrasound with phthalic acid crystallization, as a model compound, compared to a classical tubular flow reactor.

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a b s t r a c tThe major inorganic solid residues of chemical pulp mills include green liquor dregs, various lime residues, recovery boiler fly ash, and salt cake produced at the chlorine dioxide generator. Only a small proportion of these residues is currently utilized outside the mill area: landfill disposal and reuse at the mill are the most typically applied methods. The situation should be improved in the future for environmental and economical reasons. The focus of this review is on the separation of inorganic pulp mill residues to enhance the possibilities of their utilization. Solid-liquid separation operations, such as filtration and sedimentation, and the associated treatment processes, are described in close detail. The review aims at recognizing the most promising residues for utilization, as well as enhancing the understanding of the material balance of chemical pulp mills. The review also covers the most potential industrial applications for the utilization of residues, as well as the possibilities of using them as raw material in value-added products.

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