Table 4.

Environmental remediation applications of green ZrO₂ nanoparticles

Green material	Species	Type of treatment	Target pollutants	Main findings	Refs.
Bacterium	Pseudomonas aeruginosa	Adsorption	Tetracycline	Optimum pH 6.0	Debnath et al. (2020)
				High adsorption capacity of 526.32 mg/g, adsorption model fitted best with Langmuir model
				Reusability up to 5 cycles (81.55% after 5th cycle)
Plant	Euclea natalensis	Adsorption	Tetracycline	The best adsorptive capacity of 30.45 mg/g was obtained by response surface methodology	Silva et al. (2019)
Plant	Aloe vera	Adsorption	Fluoride	Exothermic and spontaneous adsorption between 20 and 50 °C	Prasad et al. (2014)
				Nearly 99% F– ions were adsorbed by ZrO2-based adsorbent
				Chemisorption capacity of 96.58 mg/g
Plant	Sapindus mukorossi	Adsorption	Methylene blue	Optimum adsorption conditions at pH 10, adsorbent dosage of 0.3 g, initial methylene blue concentration of 20 mg/L, and average time of 300 min	Alagarsamy et al. (2022)
				94% removal efficiency for methylene blue dye and adsorptive capacity of 23.26 mg/g
				Good recyclability: 0.1 M HCl as an efficient eluent, and three consecutive cycles
Plant	Wrightia tinctoria	Catalytic degradation	Reactive yellow 160 dye	94.58% degradation for Reactive yellow 160 azo dye	Al-Zaqri et al. (2021)
				0.9837 min−1 for first order rate constant (k1)
Plant	Lagerstroemia speciosa	Catalytic degradation	Methyl orange	Degradation percentage was at 94.58% after irradiating under the sunlight for 290 min	Saraswathi and Santhakumar (2017)
Plant	Ficus benghalensis	Catalytic degradation	Methylene blue	Optimum conditions: catalyst loading of 1.5 g/L at pH 7	Shinde et al. (2018)
				Removal of 91.22% after 240 min
Plant	Ficus benghalensis	Catalytic degradation	Methyl orange	Optimum pH 7	Shinde et al. (2018)
				Methyl orange was degraded at 69.23% after 240 min