A Survey on Nanotechnology-Based Bioremediation of Wastewater

Table 2

Comparisons between several HMR methods.

S. no.	Reference	Methods	Structure	Merits	Demerits
1.	[36, 37]	Conventional method	(i) Chemical oxidation; (ii) Reverse osmosis; (iii) Ion exchanger; (iv) Adsorption; (v) Reduction	(i) High controllability; (ii) Resistance to a big number of heavy metals	(i) High operating expenses due to low metal removal efficiency; (ii) High energy demands; (iii) Reduced soil fertility; they are all factors that contribute to secondary pollution
2.	[13, 38]	Treatment with microbes	(i) Passive and active methods of biosorption and bioaccumulation	(i) Reduces energy usage costs while also inhibiting germs; (ii) Removing odors; (iii) Improving air quality	(i) The process is restricted because of the existence of a nonbiodegradable pollutant; (ii) It produces microbial toxicity
3.	[39]	Treatment based on plants	(i) Phytoextraction; (ii) Phytostabilization; (iii) Phytodegradation	(i) Low cost; (ii) Efficient; (iii) Simple to maintain and environmentally friendly	(i) Permanence of soil amendments; (ii) Metals are leached into groundwater
4.	[6]	Treatment based on nanomaterial	(i) Adsorption; (ii) Treatment-based single-; stage; (iii) Chelation	(i) Surface impact; (ii) Quantum effect; (iii) Macro quantum effect	(i) The usage of hazardous chemicals, agglomeration; (ii) Limited real-life uses and scarcity of comprehensive investigation