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In recent decades, reports from around the globe indicate an increase in natural organic matters (NOMs) in surface waters, which has a negative impact on drinking water purification and causes problems such as the taste and color of water, reducing the amount of dissolved oxygen in water, causing membrane fouling in the filtration process, and acting as a precursor for the formation of an antiseptic by-product. This work used the adsorption process to evaluate the elimination of natural organic compounds in aquatic environments. Ethylenediaminetetraacetic acid (EDTA) as a crosslinker for chitosan (CTS) and N, N-methylenebisacrylamide as a crosslinker for polyacrylamide (PAM) were used to prepare humic acid (HA) adsorbents utilizing a two-step procedure. The FTIR spectroscopy proved the EDTA cross-linking agent was effective with the semicrosslinking CTS/PAM hydrogel. CTS/PAM/EDTA double network (DN) hydrogel exhibited a higher HA adsorption capacity ( q e = 107.7 mg/g) than CTS/PAM ( q e = 59.3 mg/g) at pH = 7 and an initial concentration of 60 mg·L−1 during 60 min. Also, results demonstrate that CTS/PAM/EDTA DN hydrogels showed faster adsorption kinetics than CTS/PAM. [ABSTRACT FROM AUTHOR]

The financial crisis which started in 2007 is considered to be responsible for the creation of the greatest financial dislocations since the Great Depression in the 1930s causing a drop in the international trade. In this respect, shipping market as the main service provider to international trade experienced a downfall wherein many shipping companies lay-upped or scrapped their vessels. The main purpose of this research is to evaluate the changes in Iranian liner shipping connectivity index caused by economic recession. For this purpose, this paper studies the Iranian economy from 2007 to 2009, i.e. the recession period, and evaluates the effects of world financial crisis on the Iranian shipping market. [ABSTRACT FROM AUTHOR]