Pedogeochemistry of hortic anthrosol from Copou greenhouse – Iaşi (I)

The soil from Copou greenhouse – Iasi is a mixic-proxicalcaric-hipohortic entianthrosol (profile IS.1), associated with proxicalcaric–hortic-anthrosol (profile IS.2). Characteristic for this anthrosol is the formation at depth of 12–48 cm of Ahok horizons, proto-frangipanes or frangipanes, which determined the differential evolution of pedogeochemical processes in soil profiles (geochemical segregation phenomena). The studied soils fall within the class of medium and fine textured, the dominant particles size fractions (with very close weight) being sand and clay. The migration and accumulation tendency of fine particles size fractions at Ahok(x)2 horizon level represent one of the conditions for frangipane horizons formation and developing of geochemical segregation phenomena. For upper horizons of profiles are characteristics neutral conditions – weak alkaline and moderately oxidizing, and for bottom horizons are characteristic neutral conditions – weak acid and moderately reducing. Following the total soluble salts content (variation limits: 152.92–688.02, average: 382.87 mg / 100 g soil), the upper horizons are highly salinized (Apk1) and moderately salinized (Apk2, Ahok(x)1 and Ahok(x)2), and the bottom horizons are weak salinized. The total phosphorus content varied between 94.57–768.05 μg P2O5/g soil, with an average of span by 53.95 % from total phosphorus. The inorganic phosphorus represents 46.03 % from total phosphorus, and the organic phosphorus is 53.95 % from total phosphorus. The phosphorus extractable in acetate – lactate, non-occluded phosphorus, varied between 90.09–740.09 μg P2O5/g soil, with an average of span by 366.50 μg P2O5/g soil (which represents 94.73 % from total phosphorus)

Fragipanization phenomenon – effects on soils pedogeochemistry from protected areas (greenhouses and solariums)

In this paper are presented several new aspects related to the effects of fragipanization phenomenon on pedogeochemical processes in particular case of soils from protected areas (greenhouses and solariums). A special attention was paid to dynamic evolution of macro- and micro-elements in conditions of soils from protected areas, affected by fragipanization phenomenon, and to the correlation between these and pedogeochemical segregation and salinization processes. In addition, were highlighted a number of issues relating to the conditions of emergence and dynamics of the frangipane in soils from protected areas. The fragipane represents both a degradation phenomenon and an initiator for soil degradation phenomena. The formation of fragipane horizons is directly correlated with the apparition and development of pedogeochemical segregation, compaction and salinization processes that have strong negative influence on pedological and agrochemical characteristics of soils. The impacts fragipane is highlights, in general, by: (i) the discontinuity of water circulation in the soil profile, (ii) contrasting physico-chemical conditions between the upper and lower horizons, (iii) particular and atypical evolutions of the organic matter dynamics, speciation processes and inter-phase distribution of macro- and micro-elements etc., (iv) simultaneously with the formation horizons fragipane (emphasis segregation pedogeochimice) are rapidly degraded the physical-chemical and agrochemical characteristics of soils, with negative effects on their productivity and quality of obtained agricultural products

The evaluation of factors affecting sorption of pentachlorophenol in soil

The release of persistent organic pollutants (POPs) derived from different industrial processes represents an important source of environmental contamination. Pentachlorophenol (PCP) is a highly chlorinated organic compound that has been extensively used as a broad spectrum biocide, particularly in the wood preservation industry. Due to its stable aromatic ring structure and high chlorine content, PCP is persistent in the environment, and it has become one of the most widespread contaminants in soil, sediments and water. In soil, the fate of POPs is governed by their interactions with reactive soil colloids. The soil properties as well as the chemical properties of the pollutants, control its bioavailability and transport, thus, affecting further remediation processes. The main objective of the present work was to study the sorption of pentachlorophenol in soil, collected from Iasi area (Romania). The experiments were performed in batch mode. Interest was directed towards the effects of contact time (0-72 h), initial pollutant concentration (5 - 20 mg L-1), pH and temperature (10 - 50oC). The sorbed amounts of PCP increased with increase in contact time and initial concentration and reached the equilibrium after 24 h. Pentachlorophenol sorption increase with temperature in the range of 10-25oC, suggesting an endothermic process, and decrease when the temperature increased from 25 to 50°C. The results indicated that lower temperature (i.e. 10 to 25°C) was favorable for the sorption process. The high temperature (50°C) might affect the physicochemical properties of soil therefore; the sorption PCP on soil was significantly reduced

The extraction of Zn(II) in aqueous PEG (1550)-(NH4)2SO4 two-phase system using Cl- ions as extracting agent

The extraction of Zn(II) in an aqueous PEG (1550) – (NH4)2SO4 two-phase system as a function of several experimental parameters was studied. PEG-based aqueous two-phase systems are composed of two immiscible phases: a polymer-rich phase and a salt-rich phase, which can be used for extraction experiments. In the absence of a suitable extracting agent, for the system consisting of a mixture of equal volumes of 40 mass% PEG and 40 mass% (NH4)2SO4 aqueous solutions, Zn(II) remained predominantly in the salt-rich phase. Variation of the pH of the salt stock solution did not change very much the extraction efficiency. By adding chloride ions, an enhancement of the Zn(II) extraction was observed. The Zn(II) extraction efficiency in presence of Cl- depends on the acidity of the salt stock solution and on the concentration of chloride ions added into the system

The Separation and the Concentration of Minerals from the Zeolitic Volcanic Tuffs. Analytical Composition

The separation and concetration of minerals from zeolitic volcanic tuffs represent one of the problems for which the literature not offer, to much practically solutions. The experimental strategy used by as, for the separation minerals from zeolitic volcanic tuffs to comprise the following methods: heavy liquids separation; magnetic separation and electrophoresis separation. For zeolites, silica polymorphs, feldspars and other minerals separated from zeolitic volcanic tuffs, the work eighth conditions and the proper experimental strategy efficiency has been estabilish. The purity for mineral fractions can be separated has been between 95.0 – 99.6 %

The Separation and the Concentration of Minerals from the Zeolitic Volcanic Tuffs. Analytical Composition

The separation and concetration of minerals from zeolitic volcanic tuffs represent one of the problems for which the literature not offer, to much practically solutions. The experimental strategy used by as, for the separation minerals from zeolitic volcanic tuffs to comprise the following methods: heavy liquids separation; magnetic separation and electrophoresis separation. For zeolites, silica polymorphs, feldspars and other minerals separated from zeolitic volcanic tuffs, the work eighth conditions and the proper experimental strategy efficiency has been estabilish. The purity for mineral fractions can be separated has been between 95.0 – 99.6 %

In Situ Functionalization of Iron Oxide Particles with Alginate: A Promising Biosorbent for Retention of Metal Ions

In this study, alginate extracted from marine algae biomass was used for the functionalization of iron oxide particles obtained in situ. This procedure ensured a complete recovery of the alginate from the aqueous solution obtained after extraction and allowed the preparation of a new biosorbent. The obtained iron oxide microparticles functionalized with alginate (Alg-Fe3O4-MPs) were analyzed (FTIR spectrometry, energy dispersive X-ray spectroscopy and scanning electron microscopy), and their biosorptive performance was tested for the removal of Cu(II), Co(II) and Zn(II) ions. The optimal conditions were established as pH = 5.4, adsorbent dosage of 2 g/L, contact time of minimum 60 min and room temperature (23 ± 1 °C). The retention of metal ions was quantitative (99% for Cu(II), 89% for Co(II) and 95% for Zn(II)) when the concentration of metal ions was less than 0.80 mmol M(II)/L. The Langmuir model was found to be the best fitted model for the equilibrium data, while biosorption kinetics followed the pseudo-second order model. Biosorption processes were spontaneous (ΔG0 < 0), endothermic (ΔH0 > 0), and accompanied by an increase in entropy (ΔS0 > 0). The high maximum biosorption capacity of Alg-Fe3O4-MPs and its good regeneration highlight the potential of this biosorbent for applications in decontamination processes

VALORIZATION OF LOW-COST NATURAL MATERIALS IN DEPOLLUTION PROCESSES OF WASTEWATER

Abstract. The adsorption on non-conventional and low-cost materials for removal of toxic heavy metals and oil products from aqueous media has become important in the last years, because is an effi cient and cost-effective alternative compared to traditional chemical and physical remediation, and also other decontamination techniques. The good effi ciency, minimization of secondary (chemical or biological) wastes and low cost of adsorbent materials, are only few main advantages of adsorption that can be used for the removal of such pollutants in high volumes of aqueous solutions, being thus more adequate for large scale applications. In this paper, are presented the adsorptive characteristics of a low-cost material that are abundant in our region, namely: Romanian peat moss from Poiana Stampei (Romania), for the removal of different toxic heavy metal ions (Pb(II), Hg(II), Co(II) and Ni(II)) and oil products from aqueous media. The experiments have concerned the infl uence of several experimental parameters (initial solution pH, adsorbent dose, initial heavy metals concentration, contact time, and temperature) on the heavy metals and oil products removal effi ciency. The most important conditions for desorption of heavy metal ions from loaded-materials, required for their regeneration are also presented

VALORIZATION OF LOW-COST NATURAL MATERIALS IN DEPOLLUTION PROCESSES OF WASTEWATER

In this paper, are presented the adsorptive characteristics of a low-cost material that are abundant in our region, namely: Romanian peat moss from Poiana Stampei (Romania), for the removal of different toxic heavy metal ions (Pb(II), Hg(II), Co(II) and Ni(II)) and oil products from aqueous media. The experiments have concerned the influence of several experimental parameters (initial solution pH, adsorbent dose, initial heavy metals concentration, contact time, and temperature) on the heavy metals and oil products removal efficiency. The most important conditions for desorption of heavy metal ions from loaded-materials, required for their regeneration are also presented

Application of <i>Saccharomyces cerevisiae</i> in the Biosorption of Co(II), Zn(II) and Cu(II) Ions from Aqueous Media

Yeast biomass is considered a low-cost material that can be successfully used for the biosorption of metal ions from aqueous solution, due to its structural characteristics. This study evaluates the biosorptive performance of Saccharomyces cerevisiae in the biosorption of Co(II), Zn(II) and Cu(II) ions from aqueous media in batch mono-component systems. The influence of solution pH, biosorbent dose, contact time, temperature and initial metal ions concentration was examined step by step, to obtain the optimal conditions for biosorption experiments. Maximum uptake efficiency for all metal ions on this biosorbent was obtained at: pH = 5.0, 4.0 g biosorbent/L, room temperature of 23 °C, and a contact time of 60 min, and these were considered optimal. The equilibrium results were analyzed using Langmuir, Freundlich and Dubinin–Radushkevich isotherm models, while for the modeling of the kinetics data, three models (pseudo-first order, pseudo-second order and intra-particle diffusion) were used. Dubinin–Radushkevich isotherm model and the pseudo-second order model showed the best fit with the experimental data obtained at biosorption of Co(II), Zn(II) and Cu(II) ions on Saccharomyces cerevisiae. Both maximum biosorption capacities and pseudo-second rate constants follow the order: Co(II) > Zn(II) > Cu(II), suggesting that the structural particularities of metal ions are important in the biosorption processes. Based on the obtained equilibrium and kinetic parameters, the biosorption mechanism is analyzed and the possible applications are emphasized