dyadak Posted December 15, 2009 Report Share Posted December 15, 2009 Abstract In this thesis adsorption and desorption features were studied in details in three samples from the soil of Palestine. Soil samples were red soil, chalk soil, and sandy soil according to American Society for Testing and Materials (ASTM) scale for the classification of the soil. Adsorption and desorption rates on soil samples were calculated from kinetic studies. The values varied based on the type of soil. Maximum specific adsorption capacities (qmax) for soil samples using Langmuir model, were as follows: 0,387 (red soil), and 0,281 (chalk soil), and (0.075) sandy soil mg / g of endosulfan. Maximum adsorption was measured in red soil followed by chalk soil, but it was the least for the sandy soil. Also, the proportion of organic matter play a major role in both processes adsorption and desorptio on soil samples. _SetupBidi('source'); here was a significant reduction in the process of Adsorption in soil samples compared with the decline in pH. Desorption was higher at both acidic and alkaline pH ranges compared to neutral pH. Both the increase in temperature and concentration increase the adsorption and desorption in all soil samples. Finally, the results showed that the mobility of endosulfan, is more possible in the sandy soil followed by red, followed by chalk soil This may be attributed to the crystal lattice of red soil that play an important role in both processes adsorption and desorption, as it could be a major role for chemical and biological processes that play a role in the other soil samples. Full Article Adsorption and desorption characteristics of endosulfan pesticide from three soils in Palestine) Quote Link to comment Share on other sites More sharing options...
freeztar Posted December 15, 2009 Report Share Posted December 15, 2009 Welcome to Hypography, dyadak. As this is a discussion forum, we discourage posts that simply link to a science paper. Please describe what you find interesting in the quoted material. What questions does it raise? What further research has been done and how do the results compare? etc. In other words, what do you want to discuss? Quote Link to comment Share on other sites More sharing options...
Essay Posted December 15, 2009 Report Share Posted December 15, 2009 Abstract Both the increase in temperature and concentration increase the adsorption and desorption in all soil samples. How could an increase in concentration cause increases in both adsorption and desorption?Adsorption seems to make sense, but desorption... with increased concentration? ~ p.s. ...unless it's increased concentration of some eluent. Quote Link to comment Share on other sites More sharing options...
Essay Posted December 19, 2009 Report Share Posted December 19, 2009 Abstract In this thesis adsorption and desorption features were studied in details in three samples from the soil .... Also, the proportion of organic matter play a major role in both processes adsorption and desorptio on soil samples.Regarding my previous clumsy question:...or does the "sorption affinity" of the soil decrease... with increasing concentration of some pesticide/PAH......as happens with biochar.=== Well I learned something new today! Seems to me that normal, black-carbon rich soils (and certainly soils amended with biochar) should show some unique non-linear sorption isotherms. I've just started reading "Sorption properties of 'pure' biochars" (*) and now see there are lots of possibilities.Compared to poorer soils and fresh plant material which show linear sorption properties, biochar can show a hysteresis between the adsorption and desorption isotherms... "especially at low ...concentrations" of aromatics. *(p.290) Lehmann (2009) Biochar for environmental management:Amazon.com: Biochar for Environmental Management: Science and Technology (9781844076581): Johannes Lehmann, Stephen Joseph: Books http://www.amazon.com/Biochar-Environmental-Management-Science-Technology/dp/184407658X see also: Journal of Agricultural and Food Chemistry (ACS Publications)Yang & Sheng;Sorption and Desorption Behaviors of Diuron in Soils Amended with CharcoalJ. Agric. Food Chem., 2006, 54 (22), pp 8545–8550DOI: 10.1021/jf061354yPublication Date (Web): October 11, 2006Copyright © 2006 American Chemical Society Environmental Science & Technology (ACS Publications)Yang & Sheng;Enhanced Pesticide Sorption by Soils Containing Particulate Matter from Crop Residue BurnsEnviron. Sci. Technol., 2003, 37 (16), pp 3635–3639DOI: 10.1021/es034006aPublication Date (Web): July 12, 2003Copyright © 2003 American Chemical Society &Sander M., and J.J. Pignatello. 2007. On the reversibility of sorption to black carbon: distinguishing true hysteresis from artificial hysteresis caused by dilution of a competing adsorbate. Environmental Science & Technology, 41, 843-849=== Non-linear and hysteretic! What more could you want from soil?:Alien: Now I've got my holiday reading list all set.... :) ~ ;) Quote Link to comment Share on other sites More sharing options...
baceljones Posted February 28, 2011 Report Share Posted February 28, 2011 No Alternatives to endosulfan. Horticulture industry facing major difficulty with the phase out of endosulfan in many countries. http://pesticidetruths.co.cc/2010/10/23/urgent-search-for-endosulfan-replacement-national-rural-news-agribusiness-and-general-general-stock-land/ Quote Link to comment Share on other sites More sharing options...
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