Maria Josefa Santos Yabe

Heavy metals removal in industrial effluents by sequential adsorbent treatment

Abstract A method for metal removal can be applied to industrial wastes without prior treatment using solid adsorbents such as sand, silica, coal and alumina. This study was conducted to evaluate the removal of heavy metals in an aquatic system without prior treatment. An important aspect of the proposed method was that the removal was performed on several metals at a pH range in which a given metal undergoes an adsorption process, making the method useful for wastewater treatment. Lead was the metal of most interest due to its occurrence in waste from storage-battery manufacture. After the adsorption process, the Pb concentration, as well as that of Cd, Ni, Cr and Cu, were below the detection limit. For other metals, removal was observed to be approximately 20–30% for Ca, Mg and Mn and above 80% for Cr, Pb, Ni, Cd and Cu, using alumina as an absorbent.

Metais pesados em águas superficiais como estratégia de caracterização de bacias hidrográficas

The input of heavy metals concentrations determinated by ICP-AES, in samples of the Cambe river basin, was evaluated by using the Principal Component Analysis. The results distinguishes clearly one site, which is strongly influenced by almost all elements studied. Special attention was given to Pb, because of the presence of one battery industry in this area. Some downstream samples were associated with the same characteristics of this site, showing residual action of contaminants along the basin. Other sites presented influence of soil elements, plus Cr near a tannery industry. This study allowed to distinguish different sites in the upper basin of the Cambe (Londrina-PR-BR), in accordance to elements input.

Absorption and Toxicity of Copper and Zinc in Bean Plants Cultivated in Soil Treated with Chicken Manure

The interaction between copper, zinc, and chicken manure, whenadded to soil, was studied in a greenhouse setting. Coppersulfate and of zinc chloride at concentrations of 0.5 to 2.0mmol kg-1 were added separately to pots containing 3.0 kgof dystrophic dark red latosoil (LEd) plus 1,0% (m/m) pH 4.2chicken manure. IAPAR 57 beans were used as test plant andcultivated in the experimental soils for 30 days. Plant growthin terms of dry weight and the concentrations of copper and zincin the aerial part of the plants were determined. Bean plantingswere repeated four times, at four-month intervals. A 20%decrease in dry weight was observed when amounts of copper orzinc equal to or geater than 1.0 or 2.0 mmol kg-1, respectively, were applied to the soil over an average of fourplantings. For these concentrations, the average amount of metalfound in the plant was 13.4 mg kg-1 for copper and 224.8 mgkg-1 for zinc. Chlorosis of the leaves in the bean plantswas also observed. The copper and zinc concentrations in thetreated soil were determined using different extractants. Amongthe solutions evaluated for the extraction of available zinc,1.0 M ammonium acetate, pH 4.8, showed a better correlation withthe metal concentration in the plant. As for copper, the bestcorrelation was found with the Mehlich-1 extractant.

Incorporação de CuSO 4 residual em argamassa, como método de disposição final

Residual CuSO4 was incorporated into the mass utilized for cement preparation. To a cement mass with 1:0.5:5 of cement, lime and sand to 0.25, 0.50, 0.75 and 1.00% of residual CuSO4 were added. The sulfate was mixed separately with lime and water to induce metal precipitation. The hardened test bodies were submerged in Milli-Q water for three months. No Cu was detected in the water by Atomic Absorption Spectrometry. The best proportion for mechanical resistance and porosity is 0.50%. The cement is adequate for non-structural objects.

Validation of a liquid chromatography ultraviolet method for determination of herbicide diuron and its metabolites in soil samples

Diuron is one of the most widely herbicide used worldwide, which can undergo degradation producing three primary metabolites: 3,4-dichlorophenylurea, 3-(3,4-dichlorophenyl)-1-methylurea, and 3,4-dichloroaniline. Since the persistence of diuron and its by-products in ecosystems involves risk of toxicity to environment and human health, a reliable quantitative method for simultaneous monitoring of these compounds is required. Hence, a simple method without preconcentration step was validated for quantitation of diuron and its main metabolites by high performance liquid chromatography with ultraviolet detection. Separation was achieved in less than 11 minutes using a C18 column, mobile phase composed of acetonitrile and water (45:55 v/v) at 0.86 mL min-1 and detection at 254 nm. The validated method using solid-liquid extraction followed by an isocratic chromatographic elution proved to be specific, precise and linear (R2 ˃ 0.99), presenting more than 90% of recovery. The method was successfully applied to quantify diuron and their by-products in soil samples collected in a sugarcane cultivation area, focusing on the environmental control.