Search results

The purpose of this paper is to focus on the removal of hexavalent chromium [Cr(VI)] from wastewater by using activated carbon-supported Fe catalysts derived from walnut shell prepared using a wetness impregnation process. The different conditions of preparation such as impregnation rate and calcination conditions (temperature and time) were optimized to determine their effects on the catalyst’s characteristics.

The catalyst samples were characterized using thermogravimetric analysis, scanning electron microscopy and Fourier transform infrared spectroscopy. The adsorption of Cr(VI) by using using activated carbon supported Fe catalysts derived from walnut shell as an adsorbent and catalyst was investigated under different adsorption conditions. The parameters studied were contact time, adsorbent dose, solution pH and initial concentrations.

Results showed that higher adsorption capacity and rapid kinetics were obtained when the activated walnut shell was impregnated with Fe at 5 per cent and calcined under N₂ flow at 400°C for 2 h. The adsorption isotherms data were analyzed with Langmuir and Freundlich models. The better fit is obtained with the Langmuir model with a maximum adsorption capacity of 29.67 mg/g for Cr(VI) on Fe5-AWS at pH 2.0.

A comparison of two kinetic models shows that the adsorption isotherms system is better described by the pseudo-first-order kinetic model.

“No climate change, no climate refugees”. On the basis of this theme, this paper aims to propose a method for undertaking the responsibility for climate refugees literally uprooted by liable climate polluting countries. It also considers the historical past, culture, geopolitics, imposed wars, economic oppression and fragile governance to understand the holistic scenario of vulnerability to climate change.

This paper is organized around three distinct aspects of dealing with extreme climatic events – vulnerability as part of making the preparedness and response process fragile (past), climate change as a hazard driver (present) and rehabilitating the climate refugees (future). Bangladesh is used as an example that represents a top victim country to climatic extreme events from many countries with similar baseline characteristics. The top 20 countries accounting for approximately 82 per cent of the total global carbon dioxide (CO₂) emissions are considered for model development by analysing the parameters – per capita CO₂ emissions, ecological footprint, gross national income and human development index.

Results suggest that under present circumstances, Australia and the USA each should take responsibility of 10 per cent each of the overall global share of climate refugees, followed by Canada and Saudi Arabia (9 per cent each), South Korea (7 per cent) and Russia, Germany and Japan (6 per cent each). As there is no international convention for protecting climate refugees yet, the victims either end up in detention camps or are refused shelter in safer places or countries. There is a dire need to address the climate refugee crisis as these people face greater political risks.

This paper provides a critical overview of accommodating the climate refugees (those who have no means for bouncing back) by the liable countries. It proposes an innovative method by considering the status of climate pollution, resource consumption, economy and human development rankings to address the problem by bringing humanitarian justice to the ultimate climate refugees.