Table 1.

Removal of volatile organic compounds with conventional methods

Nonbiological VOC removal method	Working mechanism	Pollutant	Catalyst	Inlet of VOC	Retention time	Removal efficiency of VOC	Advantages	Disadvantages	Reference
Absorption (wet scrubbing)	Scrubber absorbs the VOCs. This is applicable for water-soluble VOCs	Butanol	-	5 ppmv	20 ms (residence time)	90%	Regeneration of scrubbing liquid through an advanced oxidation process.	Pressure drop in packing structure. A secondary pollutant is a problem.	[23]
Incineration (Metal catalyst)	Laboratory scale tubular reactor used in the decomposition of pollutants in the presence of metal catalysts	1,2-Dichloroethane	Pt; Fe2O3	[C2H4Cl2]0 is the inletconcentration (mol/ L)	1.0 s	66–99.8%; 53–99% at 550°C	Control over retention time with operating temperature.	Disposal of waste is the problem. High energy consumption.	[24]
Ozonation	COF mineralization through hydroxyl radicals from the catalyst	Cooking oil fumes (COF)	Fe(OH)3	THC concentration of 211 ppm	0.05 s	95%	The oxidizing capability of ozone.	Extensive evaluation of catalyst performance for different VOCs.	[25]
Adsorption and ozonation	Adsorption of VOCs followed by oxidation	Methyl ethyl ketone	Alumina silicate	1.35 g m3	-	93%	Strong thermal and chemical stability.	Adsorbed byproducts decrease the adsorption capacity.	[26]
Adsorption andcondensation	Open-circuit and closed-loop flow in regeneration mode	VOCs	-	4099 ppmv	-	98.50%	Ozone and secondary organic aerosol production after VOCs reduction.	Checking theapplicability for urban areas.	[27]
Oxidization and volatilization	Anodic electrochemical oxidation of pollutants	Chloroform, benzene, trichloroethylene,and toluene	Pt/Ti, IrO2/TiIrO2/Ti, IrO2/TiIrO2/Ti, and IrO2− Ru−Pd/TiIrO2− Ru−Pd/Ti anodes are employed	150 mg/L	-	98%	Electrochemical properties of the anode in the removal of VOCs.	Selection of suitable anodes forparticular VOC. Disposal of catalyst is a problem.	[28]
Membrane separation	The capture of VOCs by a dense porous fibrous membrane	Aniline, benzene, and toluene	Poly(1-trimethylsilyl-1-propyne)	2 mL of VOC solvent	-	871 mg/g anilineadsorbed	Higher adsorption capacity.	Membranes are expensive. Aging of polymers.	[29]