*2.4.1 Heavy metals from contaminated water*

The group of Zhang et al. synthesized the porous nano-calcium titanate microspheres via a citric acid assisted modified sol-gel method and used for absorption of heavy metals like lead, cadmium, and zinc [103]. Haron et al. reported that the nano-crystalline LaGdO3 perovskite was synthesized by the co-precipitation method could adsorb heavy metal ions (Cd2+ and Pb2+) which should be the attention in an application such as wastewater treatment [104]. Zhang et al. synthesized porous nano-barium-strontium titanate via sol-gel method using sorghum straw as a template and investigate about adsorption mechanism of Pb, Zn, and Cd from contaminated water [105]. LaFeO3 nanoparticles were synthesized by Rao et al. by the sol-gel method in presence of different chelating agents and these nanoparticles utilized for an adsorbent of the removal of heavy metal ions in particular cadmium ion. The LaFeO3 sample prepared with succinic acid (SA) as a chelating agent shows a higher removal efficiency of Cd2+ ions from aqueous systems [106]. Zhang et al. investigated Sr modified LaFeO3 and its structural and catalytic activity. La0.8Sr0.2FeO3 contributed significantly enhanced activity in methane combustion and CO oxidation because the oxygen vacancies accelerated the dissociation of gaseous oxygen on the surface in CO oxidation and facilitated the diffusion of lattice oxygen from the bulk to the surface during CH4 combustion [107]. The perovskite LaAlO3 was manufactured using the co-precipitation method by Haron et al. The structural and efficiency of removal of heavy metal (Cd2+ and Pb2+) were extremely investigated by them. The adsorption performance was studied which fit with the Langmuir isotherm. The results disclosed that LaAlO3 perovskite showed high efficiency as heavy metal ions remover from the contaminated water. This adsorbent could be recycled with an EDTA solution and reprocessed with only slightly less efficient than that of the fresh sample [108]. The group of Chen et al. synthesized ternary photocatalyst ZnTiO3/Zn2Ti3O8/ZnO

**39**

**Figure 5.**

*citric acid (CA), and oxalic acid (OA) [106].*

*Lead-Free Perovskite Nanocomposites: An Aspect for Environmental Application*

heterojunction which displays excellent performance for the degradation of organic pollutants as well as reduction of heavy metal Cr(VI) ions from wastewater [109]. **Figure 5** schematically represent the heavy metal ion (Cd2+) adsorb with LaFeO3

The growing population in our globe, demands to clothe and increase with the taming sense of fashion and lifestyle thus textiles are contrived to meet the growing demands. In several countries such as India and Sri Lanka; the production of textile becomes their source of income that subsidizes their gross domestic product (GDP). However, this has brought both significances to such countries either in a positive way which is an enhancement of the economy or in a negative way indorsed to environmental pollution. The textile industries have been adapted as the worst reprobates of pollution contributors [110]. Especially, in India, according to the Central Pollution Control Board [111], a total of 2324 textile industries are set up. The textile industries employ different types of dyes for the manufacturing of various fabric materials. In reality, about 1 million different dyes are found in the market [112] and roughly 700,000 tons of artificial dyes are produced per year [113]. The disposal of dyes in waters exemplifies a severe environmental issue due to the coinciding presence of various types of pollutants [114–116]. All traditional methods used for the treatment of dyes and/or heavy metals have limitations because of cost, efficiency and operational complications. Among all of them, adsorption was exposed as one of the most effective methods due to its simplicity in operation, adaptability, high-treatment efficiency and low cost, and hence it is extensively applied for wastewaters treatment [117–121]. The perovskite oxide La0.9Sr0.1FeO3, capped with cetyl trimethyl ammonium bromide (CTAB) cationic surfactant, and used as a sorbent for the removal of the anionic Congo red (CR) dye from aqueous solutions was reported by Ali et al. [122]. The group of Chu et al. demonstrated the efficiency of Ag-La0.8Ca0.2Fe0.94O3-δ for the removal of organic and bacterial pollutants by catalytic peroxymonosulfate (PMS) activation. The oxygen vacancies in the B-site of perovskite enhances PMS activation and The SO4• and •OH radicals enhance the biocidal activity [123]. Nanocrystalline LaAlO3:Sm3+:Bi3+ composites are used to adsorb Direct Blue-53 (DB-53) dye was reported by Pratibha et al. [124]. This adsorbent is good and promising in the adsorption capacity and is advantageous in the elimination of toxic and non-biodegradable pollutants from water. The group of Dong et al. hydrothermally synthesized perovskite BaZrO3 in the form of hollow micro- and nano-sphere. This size-tunable BaZrO3 hollow nanospheres exhibited an excellent adsorption performance for reactive dyes in acidic conditions and can be used as excellent circular adsorbents for removing reactive dyes. They show the adsorption capacities are over

*Representation of the adsorption process over LaFeO3 nanoparticles surfaces prepared using succinic acid (SA),* 

*DOI: http://dx.doi.org/10.5772/intechopen.93052*

perovskite prepared with the different chelating agent.

*2.4.2 Heavy metals in wastewater from the textile industry*

#### *Lead-Free Perovskite Nanocomposites: An Aspect for Environmental Application DOI: http://dx.doi.org/10.5772/intechopen.93052*

heterojunction which displays excellent performance for the degradation of organic pollutants as well as reduction of heavy metal Cr(VI) ions from wastewater [109]. **Figure 5** schematically represent the heavy metal ion (Cd2+) adsorb with LaFeO3 perovskite prepared with the different chelating agent.
