Iranian, French Nano-Scientists Cooperate to Save Polluted Waters

Organic dyestuffs are considered as major sources of environmental pollutants. Therefore, removal of these materials from waste waters, through a practical and efficient method, seems essential.

Among the alternatives proposed for removing these water contaminants like textile dyes, organic compounds, agricultural pesticide wastes, etc. during recent years, are the advanced oxidation processes (AOPs) especially suitable for lower pollutants’ concentrations.

According to the Iranian Nanotechnology Initiative Council (INIC), in general, AOPs include all processes by which active hydroxyl radicals are liberated in water through different mechanisms. Due to their high oxidizing potentials, the mentioned radicals are capable of complete degradation of most pollutants.

A. R. Khataee, the Iranian scientist conducted several surveys on eliminating three different textile dyes prepared in diluted solutions. In his sets of experiments, he tried to apply titanium dioxide nanocatalyst in an oxidative photocatalytic reaction in order to improve pollutants’ removal.

In this research, first the purchased commercial grade titanium dioxide nanoparticles were characterized by means of XRD, SEM, TEM, BET tests. Then, nanocatalyst particles of titanium oxide were stabilized upon glassy plates using thermal treatments.

With the aid of these prepared plates, photocatalytic conversion of three different dyes was investigated carefully.

The results of this research work successfully demonstrated almost complete removal of acidy organic pollutants thanks to the applied nanoparticles.

The complete details of this work, collaborated by Marie-Noëlle Pons from Nancy Université, France, are published in the Journal of Hazardous Materials, volume 168, pages 451 to 457, 2009.

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THE BAGMATI ACTION PLAN (2009-2014)

The steadily increasing population and related solid waste dumping in the rivers, discharge of industrial effluents together with direct discharge of domestic sewage have made the Bagmati River and its tributaries excessively polluted. The river’s capacity to purity itself by means of interaction between biotic and abiotic characteristics of the river has been slowly failing. On the other hand, the Bagmati and its tributaries still occupy a special religious and cultural importance. It is still an important place for rituals. Unfortunately, the structures around the ghats where rituals are performed are rapidly deteriorating. These archaeological and historical sites are in an immediate need for effective protection and management.

A recent study (KAPRIMO, 2007) on water-flow and water quality has indicated a very alarming situation and classified most parts of the rivers within Kathmandu valley excessively polluted. The pollution of these rivers has deeper impacts on overall urban environment and human health. However, experiences from China, shows that it is possible to restore and conserve polluted rivers such as Nanjing Qinhuai River, if there is a will and determination to do so.

The Bagmati River is currently used for different purposes, including: (1) the major sources for municipal, industrial, and irrigation water for Kathmandu Valley; (2) cultural and religious practices; (3) disposal of water borne effluent and deposition of solid waste along the banks; (4) extraction of sand, (5) spaces for public infrastructures e.g. roads and water tanks, and (6) preferred zones for squatters and other encroachments. However, there is a serious lack of planning, regulations, enforcement, and implementation of appropriate and effective programmes. To address the complicated issue of Bagmati conservation, there is need for developing a comprehensive and practical Bagmati Action Plan (BAP) to fill the gap of an updated guiding document to address the key issues.

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