Studiul cinetic al îndepărtării ionilor de Pb(II) şi Hg(II) din medii apoase pe biomasă de rapiţă

In this study, the removal of Pb(II) and Hg(II) ions from aqueous solution using rapeseeds biomass was examined in batch systemsas a funtion of contact time. The results obtained for the removal of each studied metal ion were analyzed using three kinetics models: prseudo-first order, pseudo-second order and intra-particle diffusion, in order to elucidate the mechanism of the removal process. For both studied metal ions, the experimental data are well described by the pseudo-second order kinetics model. Theseresults can be used for to highlight the potential applicability of rapeseeds biomass as low-cost biosorbent in the clean-up of aqueous effleunts, containing toxic heavy metals

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)

Recent advances in biosorption of heavy metals: support tools for biosorption equilibrium, kinetics and mechanism

Heavy metals are increasingly present in industrial wastes and effluents, which can generate serious concerns for environmental quality and human health. Consequently, there is a continuous expansion of researches for new approaches and developments to guarantee environmental cleaning-up. Although there are some physico-chemical established methods for the removal of heavy metals from various environmental compartments, biosorption gains further confidence as a reliable alternative compared to classical technologies, which are expensive and sometimes unreliable. This paper aims to analyze the biosorption as a biotechnological strategy for the decontamination of aqueous effluents containing heavy metal ions, in terms of its potential for metal immobilization and uptake. The paper also focuses on the most important parameters affecting the removal of heavy metals by various categories of biosorbents both living and non-living forms of biomass and provides new alternatives for modeling and optimization of process equilibrium and kinetics. A special attention was paid to biosorption mechanism, as a factual challenge for process optimization and scale-up. The potential benefits and problems associated to metal removal by biosorption are highlighted.Roumanian National Authority for Scientific Research, CNCS – UEFISCDI, project number PN-II-ID-PCE-2011-3-0559”, Contract 265/2011

Optimizarea parametrilor de biosorbţie pentru reţinerea ionilor de Cu(II) pe biomasă de alge marine roşii şi verzi

Marine algae are an important biomass resource because of the many properties they have in solving various environmental problems such as the ability to decontaminate wastewater, soil decontamination, soil fertilization, etc. Heavy metal pollution is a problem for the environment. The development of industrial activities has led to increased emissions of heavy metals into the environment, with negative consequences for soils, plants, rivers and waters. Therefore, it is necessary to find appropriate methods that should be environmentally friendly in removing metal ions in a more efficient and inexpensive way. In this paper we optimized the biosorption parameters (pH, initial concentration and contact time) for the retention of Cu (II) ions on algae biomass, using two types of marine algae: a red one Callithamnion corymbosum sp. and a green one -Ulva lactuca sp. from aqueous solution

Possibility of using algae biomass for removing Pb (II) ions from aqueous solutions

In this study, the possibility of using algae biomass for removal of Pb(II) ions from aqueous solutions was studied. This material was chosen as adsorbent in this study due to being of its natural, renewable and low-cost. Batch adsorption experiments were carried out as a function of initial solution pH, adsorbent dose, initial Pb(II) concentration and contact time at 22 °C. About 0.2 g of algae biomass was found to be enough to remove 93 % of 175.6 mg/L Pb(II) from 25 mL of aqueous solution in 30 min. The optimum initial pH value was found to be 5.0. The Langmuir and Freundlich isotherm models were used to describe the equilibrium data and the isotherm constants were determined. The experimental adsorption data were fitted to the Langmuir isotherm model. The maximum adsorption capacity was 105.26 mg/g, at studied temperature. The biomass of the marine algae Ulva lactuca sp. demonstrated a good capacity for Pb (II) ions adsorption, and can be considered a potential adsorbent for effluents treatment process

Eficienţa îndepărtării ionilor de Zn(II) din medii apoase prin biosorbţie pe diferite tipuri de deşeuri de biomasă

In this study was analyzed the ability of three types of waste biomass for removal of Zn(II) from aqueous solution. The three types of biosorbents that havebeen used in experiments are:sawdust, mustard waste and soybeanwaste. These materials, which are waste from various branches of industry, can be used to remove metal ions from aqueous solutions, thus helping to reduce environmental pollution.The results for the influence of initial Zn(II) ions concentration and contact time on the removal efficiency from aqueous media were modelled using two isotherm models (Langmuir and Freunlich) and two kinetics models(pseudo-first order model and pseudo-second order model). The evaluation of biosorptive potential of these three types of waste biomasses in the removal processes of Zn(II) ions from aqueous solution was performed using the parameters obtained from the modellin

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

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