A research team from the Autonomous University of Barcelona works to develop new methods based on reusing vegetal waste to remove toxic metals from wastewaters. They have performed an experiment in ALBA Synchrotron in order to understand how pine biomass captures heavy metals present in polluted water.

Cerdanyola del Vallès, 5th June 2018. The development of low cost techniques to capture toxic metals from the environment is one of the most important objectives in environmental sciences. These metals are found in wastewaters due to the pollution produced by different industries. A recent study performed at the ALBA Synchrotron aims to obtain fundamental information for developing water treatments suitable for capturing these pollutant metals.

De dreta a esquerra els investigadors Roberto Boada, Jingjing Zhao i Cristina Palet, i  Carlo Marini d'ALBA  Biomassa de pi

From right to left researchers Roberto Boada, Jingjing Zhao and Cristina Palet, with Carlo Marini from ALBA.

Biomass is an organic material able to adsorb metals from the environment. The adsorption process is based on the retention of pollutants on a solid surface called adsorbent. In this study, pine biomass and other derived materials such as pine biochar (biomass treated at high temperature) and pine biomass loaded with titanium oxide were investigated as adsorbents. Once powdered, the adsorbents were put in contact with water samples containing a mixture of heavy metals: chrome, copper, cadmium and/or lead. These samples were analyzed with the X-ray Absorption Spectroscopy technique, available at CLAESS beamline in ALBA. This beamline enables researchers to detect the different chemical species present in the sample thanks to their absorption spectrum. This technique with synchrotron light enables them to directly study the change that these heavy metals suffer when they come into contact and are adsorbed on the biomass. The preliminary work carried out before the experiment performed at ALBA showed that the biomass with titanium oxide particles has a better adsorption capacity for the pollutants studied.

From adsorption to reuse

“This is the first time that we study biomass and its interaction with heavy metals at CLAESS beamline in ALBA (using X-ray absorption spectroscopy). This method of adsorption with biomass can be very helpful in regions with abundance of reusable vegetal wastes, as it happens with coffee, sugarcane or cocoa production” says Cristina Palet, the responsible of the study; moreover, this technique has another huge advantage because since the metals adsorbed on the biomass could be retrieved and, in the best case, reused by the industry.

Among all the separation techniques that are used for the extraction of heavy metals from polluted waters, adsorption is one of the most advantageous due to its high efficiency, low cost and easy handling. Biomass is a natural material from vegetal origin which emerges as an economic and ecological alternative to traditional adsorbents.

One of the studied metals in this investigation is chrome. This element (in Cr6+ form) is one of the most dangerous for the environment due to its high toxicity for living beings. Chrome is released in certain quantities into wastewaters primarily by textile and leather industries during the tanning processes.

Once these results had been analyzed in detail, they hope to get a deeper insight on how the adsorption processes of biomass in general, and pine biomass in particular works. This will enable to get an easier and more ecological method for removing heavy metals from wastewaters.



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