Removal of heavy metals from wastewater and drinking water is of great importance due to their high toxicity. Most of the heavy metal salts are soluble in water and cannot be separated by ordinary physical separation methods. Numerous methods have been widely applied for removal, extraction and separation of heavy and precious metals from wastewater as well as other environmental samples. For the separation of various elements, ion- exchange has been used more extensively than any other technique. Furthermore, the removal of metal ions with the help of chelating resins using batch equilibration method has gained rapid acceptance because of its wide variety of sorbent phases, high degree of selectivity, high loading capacity and enhanced hydrophilicity. The main objective is the preparation of insoluble functionalized polymers which can provide more flexible working conditions together with good stability and high capacity for the adsorption of certain metal ions. Based on the hard and soft acids and bases theory (HSAB), the ion- exchangers with functional groups containing S donor atoms interact strongly with the soft acids like precious metal ions.
The heat exchanger is major element as far as heat transfer and energy conservation is concern. There are so many types of heat exchangers available but due to wide range of design possibilities, simple manufacturing, low maintenance cost, cross flow and counter flow heat exchanger extensively used in petroleum, petrochemical , air conditioning, food storage and other industries. The shell and tube heat exchanger is widely used in industries as a chiller plant for transfer waste heat from the injection molding machine to the cooling water for improve the efficiency of the injection molding machine. The transformations of the waste heat from the injection molding machine to the cooling water are dependent on the heat exchange capacity of heat exchangers. To increase the heat exchange capacity of heat exchanger optimization is done which seeks to identify the best parameter combination of heat exchangers. Nine models are made on the basis of taguchi method in NX 10.00 and CFX analysis is carried out in ANSYS 14.5. Result obtained from that gives the best dimension of heat exchanger for minimum outlet temperature of water.
This work addresses the problem of using seawater for cooling and the associated environmental problems caused by the usage and discharge of biocides. The discharged biocide and its byproducts are toxic to aquatic lives and must be decreased below certain limits on load prior to discharge. The conventional approach has been to add biocide removal units as an end-of-pipe treatment. This work introduces an integrated approach to reducing biocide discharge throughout coordinated strategies for in-plant modifications and biocide removal. Process integration tools are used to reduce heating and cooling requirements through the synthesis of a heat-exchange network. Heat integration among process of hot and cold streams is pursued to an economic extent by reconciling cost reduction in utilities versus any additional capital investment of the heat exchangers. Other strategies include maximization of the temperature range for seawater through the process and optimization of biocide dosage. This new approach has the advantage of providing cost savings while reducing the usage and discharge of biocides. Usefulness of this approach is illustrated on a case study.
Heat exchangers play a vital role in almost all fields of industry ranging from condensers and evaporators in refrigerating units to radiators of automobiles . The strive for obtaining better energy efficiency and cost savings has made the industry to constantly upgrade the technology associated with heat exchangers to improve their heat transfer efficency , reduce the size and also to lower production costs .This has resulted in research into various tube shapes used in heat exchagers including wing-shaped tubes that can improve the heat exchange efficiency .A study was carried out to compare the performance of heat exchangers with staggered banks of tubes with wing-shaped cross sections and cylindrical tubes under turbulent flow conditions. Detailed 2D- numerical simulations of fluid flow and heat transfer were performed for various pitch to diameter ratios using Computational Fluid Dynamics . When compared to the normal cylindrical tubes better heat exchange was observed in wing-shaped tubes which could be due to more attached flow happening in this case due to the wing-shape.
An ion-exchange is an established unit operation and is an important supplement to procedures such as filtration, distillation and adsorption. In the laboratories, ion-exchangers are used as an aid in analytical and preparative chemistry. However, the most important application is still the purification and demineralization of water, a perennial challenge since the time of Aristotle and Moses and a task which the growth of population and industries has made even more pressing than ever before. The inorganic ion-exchangers exhibit high selectivities for specific ions resulting in the separation factors much larger than those exhibited by organic resins. The inorganic ion-exchangers unlike organic ion-exchangers have rigid structures and do not undergo appreciable dimensional change during the ion-exchange reactions. The rigid structure leads to specific and unusual selectivities. Earlier attention was focused on hydrous oxides since it was known that they sorbed or co-precipitated many ions. It was soon discovered that hydrous oxides combined with anions such as phosphates, vanadates, molybdates and antimonates produced superior ion-exchangers.
Ion exchange is an exchange of ions between two electrolytes or between an electrolyte solution and a complex. In most cases the term is used to denote the processes of purification, separation, and decontamination of aqueous and other ion-containing solutions with solid polymeric or mineralic 'ion exchangers'. Ion exchange resin beads. Typical ion exchangers are ion exchange resins (functionalized porous or gel polymer), zeolites, montmorillonite, clay, and soil humus. Ion exchangers are either cation exchangers that exchange positively charged ions (cations) or anion exchangers that exchange negatively charged ions (anions). There are also amphoteric exchangers that are able to exchange both cations and anions simultaneously. However, the simultaneous exchange of cations and anions can be more efficiently performed in mixed beds that contain a mixture of anion and cation exchange resins, or passing the treated solution through several different ion exchange materials. Ion exchangers can be unselective or have binding preferences for certain ions or classes of ions, depending on their chemical structure.
A number of covalently bonded zwitterionic stationary phases with inner quaternary amines and outer sulfonic acids in varying capacities was synthesized based on poly (styrene-DVB) particles by graft polymerization. The different spacer lengths and capacities are used as an investigative tool, for the retention behavior of the inorganic anions in ZIC and ZIC-HILIC modes. The results of variations of acetonitrile content, buffer concentration and mobile phase pH show that pharmaceuticals can be separated based on hydrophilic, hydrophobic and anion/cation-exchange interactions between the stationary phase and analyte. The pharmaceutical deferoxamine mesylate (DFOM) is a chelating agent which forms complexes with multiple charged metal ions of biological importance (Fe3+, Al3+) and other metals. We could demonstrate that the sulfobetaine exchangers are able to separate the Fe(III)-DFOM and Al(III)-DFOM complexes by IC-ICP-AES. Excess adsorption isotherms of water from acetonitrile were measured for ten zwitterionic stationary phases (eight sulfobetaine exchangers have been prepared and two commercially available stationary phases) using the minor disturbance method.