**6. Gaseous pollution control**

**CO:** Catalytic converter (CC) is a device which is used to convert the hazardous exhaust gases to non-hazardous exhaust gases by using the simple technique of redox reaction. The working of CC is totally based on the catalyst used. For CO control the Silver is used as a catalyst. The more the catalyst, the more the active site and fast reaction.

Catalysts were identified by BET, FTIR, SEM- EDX, XRD, XPS technologies [59]. A study revealed that ZnO–CuO created hetero-composites show selective CO detecting with T100 is in close vicinity to Topt to yield simultaneous CO detecting together with its 100% catalytic oxidation for detection devices. The initiated oxygen reacts immediately with adsorbed CO to provide desired CO detecting together with 100% CO oxidation [60]. Evidences showed that oxidative desorption of CO enhance if oxygen species are present. Fast slaking of platinum in water boost the oxidation by two processes. One of the processes is chemical oxidation by using molecular oxygen and other is Langmunir-Hinshel wood surface oxidation [61].

**SO2:** The usage of segmented multistage ammonia-based liquid spray with different oxidation potentials to remove sulfur compounds from gas. MnO2 filter are used to absorb the SO2 from the exhaust. There are many sources of SO2 production like agricultural heavy machinery, vehicles etc. In this technology MnO2 along with ozone gas is introduced and found that 90% SO2 absorption is possible with the addition of ozone. This system also has the ability to improve the NO2 exhaust [62]. The alternative methods to reduce sulfur emissions are the use of low sulfur fuel, scrubbers to lower the emissions from sulfur rich fuel. Low sulfur in fuel and use of CNG reduce the SO2 emission [63].

Oxides of sulfur (SOx) are produced and exhausted during the operations of petrochemical industry and cause harmful effects on environment. One of the technique is sulfur recovery unit (SRU) which is made up of Claus process for removal of huge amount of sulfur removal and afterward a tail gas treatment unit (TGTU) for the remaining H2S removal (SCOT process, Beavon sulfur removal (BSR) process, and Wellman-Lord process) and flue-gas desulfurization (FGD) processes

**63**

*Atmospheric Pollution Interventions in the Environment: Effects on Biotic and Abiotic Factors…*

(once-through or regenerable) [64]. Conversion of H2SO4 from SO2, which could be a great impact on reducing pollution [65]. Various approaches for controlling SO2

In this technique, SO2 is absorb by the slurry of an alkaline chemical reagent,

**Lime/limestone scrubbing:** There are many sorbents but limestone is efficient for desulfurization process. Gypsum scaling is common when the CaSO4 is more than 15%. To avoid this scaling lime stone forced oxidation process is used. In this scaling oxidation of CaSO3 CaSO4 by blustering in the air (usually in the reaction

**Sodium (hydroxide) scrubbing:** Sodium scrubbing liquor is very efficient in

**Ammonia scrubbing:** It is a unique and new technology, commonly used for desulfurization (DS) of flue gases, in this ammonia is used for DS and commercial grade crop fertilizer is produced. It is currently using by Dakota Gasification Company's (DGC) Synfuels Plant [67]. Further, electrostatic and electro-fabric precipitators are used to remove SO3 from the flue gases of coal power plants [68].

Chlorine emission control technologies are necessary to meet the low emission standards of the USEPA. A study showed that flue gases were samples and analyzed by different emission control technologies (Selective non catalytic reduction, Electrostatic precipitators and fabric filters) and found that 86.1% of chlorine is exhausted in the form of gas. HCl is found significant in samples. The exclusion efficiencies of total chloride are 15.6% by ESP and 19.0–19.7% by FFs,

An exhaust system is designed (patent) which has the ability to store NOx at temperature below 200° C and release the NOx above 200° C [70]. Rising trends of Nitrate aerosols were observed in china. The main cause is day time nitrate emissions. These can be controlled if the day time emissions of NH3 and O3 be under-control [71]. NOx emissions are very common from the burning of dried sewage sludge. It is studied that if the combustor physical and operation condition maintained than NOx emissions can be controlled about 75%. Further argued that moderate or intense low oxygen dilution is best suited option to reduce NOx with the cyclone type furnace [72]. Another study suggested that air staging can lead to higher reduction of NOx [73]. NOx can further be controlled from the diesel exhaust by controlling the temperature. It could be 90% less emission if the temperature is minimized. Flue gas treatment with ozone oxidation technology is used to remove NOx. Increase in solubility and bond breakage is the key to success for this technology [74]. The three leading stack gas treatment techniques for NOx control are catalytic reduction with ammonia, non-catalytic reduction with ammonia, and direct scrubbing of NO with simultaneous absorption of SO2. The wet processes are

*DOI: http://dx.doi.org/10.5772/intechopen.94116*

and SO2 (g) is either converted to liquid or solid.

absorbing emitted SO2. It is usually used in industrial broilers.

emissions include.

**7. Wet scrubber**

chamber) [66].

respectively [69].

**9. NOX control**

**8. Chlorine emission control**

much less developed than the dry processes [75].

(once-through or regenerable) [64]. Conversion of H2SO4 from SO2, which could be a great impact on reducing pollution [65]. Various approaches for controlling SO2 emissions include.
