Biosorción de plomo (II) en solución acuosa con biomasa de los cladodios de la tuna (Opuntia ficus indica) / Biosorption of lead (II) in aqueous solution with biomass of prickly pear cladodes (Opuntia ficus indica) / Biossorção de chumbo (II) em solução aquosa com biomassa de cladódios de pera espinhosa (Opuntia ficus indica)

Resumen Se investigó la remoción de plomo de soluciones acuosas por biomasa de los cladodios de la tuna (BCT), una especie abundante en la sierra peruana. Las propiedades físicas y químicas de la BCT se determinaron por técnicas de FTIR y SEM/ EDX. El análisis FTIR confirmó la presencia de grupos -OH, CO-C, C=O y -NH2, los cuales interactuarían con el metal. La micrografía SEM reveló que la morfología superficial de la BCT tiene porosidad adecuada para la biosorción. En un sistema discontinuo se obtuvo la más alta capacidad de biosorción (qe) con una relación masa BCT/volumen de 4 g/L, pH 4,5 y tiempo de contacto de 1 h. La biosorción siguió un modelo cinético de pseudo-segundo orden y el proceso de difusión intraparticular fue el factor principal de control de la velocidad. Los datos en el equilibrio fueron correlacionados con cinco modelos (Langmuir, Freundlich, Temkin, D-R y Redlich-Peterson) y se ajustaron mejor al modelo de Langmuir, lo que indica que el proceso se realiza en centros activos energéticamente homogéneos, el valor de qe máxima fue 50,25 mg/g. Los resultados obtenidos demuestran que la BCT puede ser usada como biosorbente eficiente para el tratamiento de aguas contaminadas con Pb (II).

Abstract The removal of lead from aqueous solutions by the biomass of prickly pear cladodes (BCT), a species found in abundance in the Sierra region in Peru, was investigated. The physical and chemical properties of BCT were determined by FTIR and SEM/EDX techniques. The FTIR analysis confirmed the presence of -OH, C-O-C, C=O and -NH2 groups which would interact with the metal. The SEM micrograph revealed that the surface morphology of the BCT shows adequate porosity for biosorption. In a discontinuous system, the highest biosorption capacity (qe) was obtained with a BCT mass/volume ratio of 4 g/L, pH 4.5 and 1 h of contact time. Biosorption followed a pseudo-second order kinetic model and the intraparticle diffusion process was the main factor controlling speed. Data at equilibrium were correlated using five models (Langmuir, Freundlich, Temkin, DR, and Redlich-Peterson) and were better fitted to the Langmuir model, which would indicate that the process is carried out in energetically homogeneous active centers, the value of qe maximum was 50.25 mg/g. The results obtained demonstrate that BCT can be used as an efficient biosorbent for the treatment of waters contaminated with Pb (II).

Resumo Investigou-se a remoção de chumbo de soluções aquosas pela biomassa de cladódios de pera espinhosa (BCT), espécie encontrada em abundância na região da Sierra, no Peru, e as propriedades físicas e químicas do BCT foram determinadas por técnicas de FTIR y SEM/EDX. A análise por FTIR confirma a presença dos grupos -OH, C-O-C, C=O e -NH2 que interagem com o metal; a micrografia SEM revela que a morfologia da superfície do BCT mostra porosidade adequada para biossorção. Em um sistema descontínuo, a maior capacidade de biossorção (qe) foi obtida com uma relação massa/volume de BCT de 4 g/L, pH 4,5 e tempo de contato 1 h. A biossorção seguiu um modelo cinético de pseudo-segunda ordem e o processo de difusão intrapartículas foi o principal fator de controle da velocidade. Os dados em equilíbrio foram correlacionados usando cinco modelos (Langmuir, Freundlich, Temkin, DR e Redlich-Peterson) e foram melhor ajustados ao modelo de Langmuir, o que indicaria que o processo é realizado em centros ativos energeticamente homogêneos, o valor de qe o máximo foi de 50,25 mg/g. Os resultados obtidos demonstram que o BCT pode ser usado como um biossorvente eficiente para o tratamento de águas contaminadas com Pb (II).

Adsorption potentialites of bio-sorbents derived from prosopis cineraria and hibiscus rosa-sinensis in the removal of methyl orange dye from polluted waters.

Leaves, stems and their ashes of Prosopis cineraria and Hibiscus rosa-sinensis have been explored for their surface sorption abilities towards Methyl Orange Dye using simulated waters. Various physicochemical parameters such as pH, time of equilibration and sorbent concentrations are optimized for evoking the sorption potentialities of the plant materials for the maximum extraction of the Methyl Orange Dye from waters. The surface sorption nature is found to pH sensitive and % of removal is maximum near pH: 3. % removal of the Dye is more with ashes than respective bio-materials. Co-anions, in fivefold excess, are found to be interfering in the order: trivalent anion>divalent > monovalent while co-cations have shown relatively less interference on the extraction of the Dye at optimum conditions of extraction. The adoptability of the methodologies developed is tested with some real industrial effluents.

New bio-sorbents in the control of chromium (VI) pollution in waste waters.

The sorption abilities of leaves powders of Bhringraj , Aerva lanata, Trianthema portulacastrum L for extracting Chromium (VI) from polluted waters have been studied with respect to various physicochemical parameters such as pH, sorption dosage and equilibrium time. The conditions for maximum removal of Chromium (VI) have been optimized. Ten fold excess of common cation ions present in natural waters, viz., Ca2+, Mg2+ , Cu2+, Zn2+, Ni2+ and Fe2+ have synergistic effect in increasing the % removal of Chromate. SO4 2—and Phosphates are found to be interfering with the extractability of Chromates but NO3 - , Chloride, Fluoride and Carbonate have marginal interference. However, the extraction has never come down below 72.0%. Maximum extractions to an extent of 96.0%, 92.0%, and 84.0% from synthetic waters are observed with the leaves powders of Bhringraj , Aerva lanata, Trianthema portulacastrum L respectively at pH:2 and at optimum equilibration time and sorbent concentrations. The methodologies developed are applied to diverse waste water samples collected from industrial effluents and polluted lakes. The procedures are found to be remarkably successful in removing the Chromiume(VI) from waste waters.

Removal of phosphates from polluted waters using bio-adsosrbents.

Increasing interest is being envisaged by environmental researchers in controlling the phosphates pollution in natural waters by evoking the surface sorption characteristics of bio-waste materials of flora origin. In the present work, a thorough investigation has been made to find powders of leaves or their ashes of different classes of plants, having the affinity towards phosphate ions. 10 plant leaves and their ashes have been found to have sensitivity towards Phosphate ion. Investigations have been made in optimizing the various physico-chemical parameters such as equilibration time, pH and sorption dosage for the maximum removal of phosphates. The % of removal is found to be increasing with the increase in pH and equilibration time. The ashes of leaves shows more sorption towards phosphates than powders of leaves.79% to 90% removal of phosphate from polluted waters are found at optimum conditions with the sorbents investigated in this work. The interference of foreign ions on the % of extraction of phosphate reveals that some divalent cations are found be synergizing the extraction and thereby % of removal of Phosphate is increased even in the presence of 500 ppm of the said ions.