BIOSORPTION OF BASIC DYES FROM POLLUTED WATER USING CHIPS FROM PINE CONES

FERNANDEZ, M.E.; NUNELL, G.V.; BONELLI, P.R.; CUKIERMAN, A.L.

Rosario

Workshop; 1st Argentinian Workshop in Environmental Science / Taller Argentino en Ciencia Mediambiental; 2009

Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario

Growing concern over pollution of water courses arising from different anthropogenic activities has led to the search of new, renewable and less expensive alternatives to the use of conventional adsorbents for the treatment of polluted waters. Among other non-living biomasses, like algae, fungi, and yeasts, several lignocellulosic wastes have been tested and have proved to be effective biosorbents for removing heavy metals and some organic compounds from wastewater. In particular, large amounts of water and chemicals are used to colour fabrics in textile industries. Spent dye baths in discontinuous dyeing, residual dye liquors and water from washing operations always contain a percentage of unfixed dye, which varies considerably depending on dye - fiber affinity and dyeing process parameters, and may constitute a severe hazard when released into the environment in wastewater. Dyeing effluents adversely impact on water courses increasing oxygen demand and affecting photo-synthetic activity of aquatic organisms. In this framework, the aim of the present work is to examine the feasibility of using natural pine cones chips from Cupressus sempervirens as a low-cost biosorbent for the removal of dyes from wastewater. Experiments in batch mode were conducted using two representative basic dyes, methylene blue and rhodamine B, from dilute aqueous solutions. The effects of solution pH and dose of biosorbent were first examined. Kinetic measurements of the biosorption process were performed, and equilibrium biosorption isotherms were further obtained. In order to represent equilibrium experimental data, Langmuir and Freundlich models were applied. It was found that pH plays a crucial role in the determination of biosorption capacities of both dyes. Biosorption of methylene blue onto the pine cones increased with the increase of pH values, while the biosorption for rodhamine B showed the opposite tendency. Kinetic measurements showed that biosorption was initially very fast for both dyes, slowing down at longer times until equilibrium was attained. The equilibrium data fitted the Langmuir model better than the Freundlich’s one. The maximum adsorption capacity for methylene blue (197.5 mg g-1) was higher in comparison with that evaluated for rhodamine B (114.5 mg g-1). Present results suggest that pine cones chips are promising biosorbents for the treatment of water polluted with cationic dyes.