21-10-2014, 02:55 PM
Abstracts: The nitration of salicylic acid by means of HNO3/AcOH is Investigated , and the results are compared with those obtained Using different nitrating systems : HNO3/H2SO4/H2O (mixed acid) , HNO3/Ac2O/AcOH, aqueous HNO3 (70% by weight) at 343 K . Little differences are found in terms of yield of the Desired product (5-nitrosalicylic acid) among HNO3/AcOH Mixture , mixed acid , and HNO3/Ac2O/AcOH systems , aqueous HNO3 giving the poorest results . However according to the data collected during the present investigation the use of the system HNO3 /AcOH presents some advantages with respect to the Others for the separation and purity of desired product , waste Minimization , and safety improvements. The reaction kinetics For the nitration of salicylic acid with this system is also Investigated . A global second – order kinetic law (one for the Substrate , one for nitric acid) is used in the analysis of the data collected for the formation of the two mononitroderivatives (3- nitro - and 5 –nitrosalicylic acids) and of the side product 2-nitrophenol Sludge minimization technologies have been available for several decades; however recent developments have brought some sludge minimization technologies to the forefront. All of the technologies utilize one or more of three basic approaches to minimize the amount of waste activated sludge produced by an activated sludge process: cell lysis, cyclic oxic environments, and long solids retention time. This paper will discuss the three basic mechanisms, will review the development of several sludge minimization technologies, and will report on the current viability of each technology as well as current research needs for each. Sludge minimization refers generally to the optimum reduction of the mass of sludge or biosolids produced at a wastewater treatment facility. The sludge minimization technologies that have emerged perform their main solids reduction mechanisms within the activated sludge process, prior to sludge stabilization and conversion to a biosolid. These are the technologies that are of interest in this paper. A fundamental understanding of the basic mechanisms available to minimize sludge production is needed prior to evaluating the various sludge minimization technologies that are emerging onto the market. From that understanding, each technology can be evaluated