Pollution, ammonia

Absorption is a unit operation that removes a solute mass or masses from a gas phase into a liquid phase. Aeration of water dissolves air into it thus, aeration is absorption. Another example of absorption is the washing of ammonia from an ammonia-polluted air. In this operation, ammonia is removed from the air by its dissolution into the water. 

Effler SW, Gelda RK, Matthews CM. 2001. Implications of industrial loads for ammonia pollution in an urban lake. Water Environ Res 73(2) 192-203. 

The easy-care treatment of cellulose fabrics uses padding with methylol-urea resins and curing them to cross-link inside the fibres. Consequently formaldehyde is the most important pollutant accompanying the easy-care finish. Alternatives were developed with resins without formaldehyde (reactive elas-tomere silicones, or dicarboxylic acids able to react with the OH groups of cellulose) but the results need still to be improved. Ammonia may also be used for improving the easy-care treatment in a mercerization-like process. This produces, on the other side, ammonia pollutants. 

The superior technical properties of BDD electrodes for the simultaneous removal of organic and ammonia pollutants are hindered by their high cost. Alternative methods of preparation of diamond electrodes that lead to lower production costs and a substrate that is not brittle like silicon or too expensive like tantalum, niobium and tungsten should be found. 

Pollution Prevention. Procedures haven been developed for recovery of composite ammonium perchlorate propellant from rocket motors, and the treatment of scrap and recovered propellant to reclaim ingredients. These include the use of high pressure water jets or compounds such as ammonia, which form fluids under pressure at elevated temperature, to remove the propellant from the motor, extraction of the ammonium perchlorate with solvents such as water or ammonia as a critical fluid, recrystalli2ation of the perchlorate and reuse in composite propellant or in slurry explosives or conversion to perchloric acid (166,167). 

Hundreds of chemical species are present in urban atmospheres. The gaseous air pollutants most commonly monitored are CO, O3, NO2, SO2, and nonmethane volatile organic compounds (NMVOCs), Measurement of specific hydrocarbon compounds is becoming routine in the United States for two reasons (1) their potential role as air toxics and (2) the need for detailed hydrocarbon data for control of urban ozone concentrations. Hydrochloric acid (HCl), ammonia (NH3), and hydrogen fluoride (HF) are occasionally measured. Calibration standards and procedures are available for all of these analytic techniques, ensuring the quality of the analytical results... 

Absorption of pollutant gases is accomplished by using a selective liquid in a wet scrubber, packed tower, or bubble tower. Pollutant gases commonly controlled by absorption include sulfur dioxide, hydrogen sulfide, hydrogen chloride, chlorine, ammonia, oxides of nitrogen, and low-boiling hydrocarbons. 

Emissions to the atmosphere from ammonia plants include sulfur dioxide (SOj), nitrogen oxides (NOJ, carbon monoxide (CO), carbon dioxide (COj), hydrogen sulfide (HjS), volatile organic compounds (VOCs), particulate matter, methane, hydrogen cyanide, and ammonia. The two primary sources of pollutants, with typical reported values, in kilograms per ton (kg/t) for the important pollutants, are as follows ... 

Particulate matter is the principal air pollutant emitted from ammonium sulfate plants. Most of the particulates are found in the gaseous exhaust of the dryers. Uncontrolled discharges of particulates may be of the order of 23 kg/t from rotary dryers and 109 kg/t from fluidized bed dryers. Ammonia storage tanks can release ammonia, and there may be fugitive losses of ammonia from process equipment. 

Raw material input to petroleum refineries is primarily crude oil however, petroleum refineries use and generate an enormous number of chemicals, many of which leave the facilities as discharges of air emissions, wastewater, or solid waste. Pollutants generated typically include VOCs, carbon monoxide (CO), sulfur oxides (SOJ, nitrogen oxides (NOJ, particulates, ammonia (NH3), hydrogen sulfide (HjS) metals, spent acids, and numerous toxic organic compounds. 

The technology is primarily applicable to the removal of inorganic fumes, vapors, and gases (e.g., chromic acid, hydrogen sulfide, ammonia, chlorides, fluorides, and SOj) volatile organic compounds (VOC) and particulate matter (PM), including PM less than or equal to 10 micrometers ( m) in aerodynamic diameter (PM,q), PM less than or equal to 2.5 m in aerodynamic diameter (PMj 5), and hazardous air pollutants (HAP) in particulate form (PM ap)-... 

Three external MSA s are considered for removing ammonia from water, air (Si), activated carbon (S2) and an adsorbing resin (S3). The data for the candidate MSA s are given in Table 4.1. The equilibrium data for the transfer of the pollutant from the waste stream to the jth MSA is given by. 

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