Eco‐efficiency,self‐sufficiency and sustainability in transport: The limits for Brazilian sugarcane ethanol policy

This paper examines the historic development of the Brazilian sugarcane ethanol sector and the largely successful attempt to create a sustainable, renewable fuel for the transport sector. The policy that resulted from this process is an example of meeting the need for sustainable transport through the consideration of location‐specific characteristics and appropriate policy. The paper then questions the current and expected trajectory of the sugarcane ethanol sector with the focus on one key question: can sustainability be exported? In this analysis, the paper identifies new threats to the sustainability of Brazilian sugarcane ethanol and potential “opportunity costs” incurred in further development and internationalization of the sector. The paper concludes that exporting sugarcane ethanol may bring unanticipated deleterious consequences, which in turn means that both policy and theory need to be more precise about how sustainable transport is defined and bounded by time and space.     

Adsorption of Remazol Red 198 onto magnetic N-lauryl chitosan particles: equilibrium, kinetics, reuse and factorial design

Purpose

The discharge of colored effluents from industries is an important environmental issue and it is indispensable to remove the dyes before the water gets back to the rivers. The magnetic adsorbents present the advantage of being easily separated from the aqueous system after adsorption by positioning an external magnetic field.

Methods

Magnetic N-lauryl chitosan (L-Cht/??-Fe₂O₃) particles were prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and vibrating sample magnetometry. Remazol Red 198 (RR198) was used as a reactive dye model for adsorption on L-Cht/??-Fe₂O₃. The adsorption isotherms were performed at 25°C, 35°C, 45°C, and 55°C and the process was optimized using a 2³ factorial design (analyzed factors: pH, ionic strength, and temperature). The desorption and regeneration studies were performed in a three times cycle.

Results

The characterization of the material indicated that the magnetic particles were introduced into the polymeric matrix. The pseudo-second order was the best model for explaining the kinetics and the Langmuir?CFreundlich was the best-fitted isotherm model. At room temperature, the maximum adsorption capacity was 267?mg?g^?1. The material can be reused, but with a decrease in the amount of adsorbed dye.

Conclusions

L-Cht/??-Fe₂O₃ is a promising material to remove RR198 and probably other similar reactive dyes from aqueous effluents.