ResumoEste estudo tem como objetivo avaliar a possibilidade de remediação de águas e áreas contaminadas com Arsênio(V) e Crômio(VI) em pH levemente ácido pela biomassa Polygonum punctatum Elliot, planta presente na imediação da lagoa da Pampulha em Belo Horizonte e em várias regiões do estado de Minas Gerais. Todos os ensaios de adsorção foram realizados em pH 5 por 24h a 25°C. A biomassa foi caracterizada por espectroscopia de infravermelho e o ponto de carga zero (PCZ) foi determinado por titulação potenciométrica. A concentração inicial e remanescente após adsorção para As(V) e Cr(VI) foram obtidas por espectrometria de absorção atômica (AAS). A capacidade de remoção para As(V) foi de 1,14 mg por grama de biomassa enquanto para Cr(VI) foi de 7,4 mg por grama de biomassa. A biomassa apresentou excelente resultado de adsorção para a espécie Cr(VI), portanto um bom potencial para aplicação para descontaminação de efluentes contendo este contaminante. Palavras-chave: Adsorção; Biorremediação; Arsênio; Cromo hexavalente. ADSORPTION CAPACITY ASSESSMENT FOR ARSENIC(V) AND CHROMIUM (VI) BY BIOMASS DERIVATIVED FROM POLYGONUM PUNCTATUM ELLIOT AbstractThis study aimed to evaluate the remediation of contaminated areas with arsenic(V) and Chromium(VI) in slightly acid pH by biomass Polygonum punctatum Elliot, which is a plant easily found in the Pampulha Lagoon in Belo Horizonte and also in various regions of the state of Minas Generais. All sorption tests were performed at pH 5 for 24 h at 25 °C. The biomass was characterized by infrared spectroscopy and point of zero charge (PZC) was determined by potentiometric titration. The initial and residual concentration after adsorption to As(V) and Cr(VI) were obtained by atomic absorption spectrometry (AAS). The As(V) uptake was 1.14 mg per gram of biomass while for Cr(VI) was 7.4 mg per gram of biomass. The biomass results showed excellent adsorption capacity toward the species Cr (VI), this presenting a good potential to be applied to the decontamination of effluents containing this contaminant.

IntroductionMetal clusters have attracted a large scientific effort in the past few years due to their potential technological applications at the nanoscale. Mixed metal systems are known to have modified and often desirable properties relative to the pure phases of the individual metal, including improved corrosion resistance, low density and malleability.¹ Metal alloys composed of aluminum and magnesium have been widely recognized to be of importance in industry and aerospace manufacturing. 2 In this work the structures and properties of Al-Mg alloys are investigated theoretically. MethodsA modified genetic algorithm (GA) was employed in the search for the potential energy minimum associated with AlxMgy (x+y<=35) clusters using an empirical Gupta many-body potential.² The GA initially generates a number of random clusters. The energy of these random clusters are minimized locally and ranked by their energies. The best clusters are then selected as parents and crossed to generate a new population. Mutation is also performed in 15% probability by rotating parts of the cluster by random amounts. Convergence is achieved when no further improvement is reached after a given number of generations.In order to avoid stagnation in a local minimum, the genetic algorithm here employed uses two different evolutionary operators: the operator history (OH) and the annihilator (A), which initiate new GA cycles in the search for different minima. 3,4