Texas Southern University
Pavani Gonnabathula is a Ph.D. Candidate and TA at Texas Southern University from Environmental and Interdisciplinary Sciences Dept., Houston, Texas. She holds Master’s and Bachelor’s degree in Pharmacy from India. She served as a Lecturer in Pharmacy for two years at Govt. Polytechnic college, India. Based on her academia she decided to do PhD. which she felt as an extension of her research career. She works in Dr. Momoh Yakubu’s laboratory investigating the effects of emerging contaminants on biomolecules using animal models; and remediation application of green synthesized metal nanoparticles for removal of emerging contaminants in wastewater and drinking water.
Removal of Trace Levels Hormonal Compounds-Endocrine Disruptors From Water by Green Synthesized Acalypha indica Silver Nanoparticles
Pavani Gonnabathula, Momoh A. Yakubu, PR Rauta and Praveen Relangi
Endocrine disrupting chemicals are natural hormones and can also be derived from plastics and pharmaceuticals. They have been found in trace amounts (ppt to ppb) in treated wastewater, and also have been detected in water samples – they are therefore difficult to remove. We have synthesized silver nanoparticles (AgNP’s) using Acalypha indica (AI) leaf extract; and use them to treat water samples spiked with hormones to determine efficiency of removal. Ag-herbal extract nanoparticles was synthesized by incubation of AI extract with AgNO3 at 800 C for 1 hour until the change of color from pale yellow to dark brown indicated the formation of colloidal silver nanoparticles. The synthesized AgNP’s were characterized by UV-Vis spectrophotometer, Zetasizer (ZS 90, Malvern, UK) for particle size and zeta potential of the AgNP’s. To investigate the effects of the AgNP’s on the removal of hormonal compounds from water, dH2O was spiked with 17-α ethynyl estradiol, β-Estradiol, Estrone, Diethylstilbestrol, 19-Norethindrone, and D-Norgestrol to the concentration of 1 and 5 ppm and to it AgNP’s (10 ppm) was added and agitated overnight. The effects of this incubation on the levels of the hormone removal was determined using HPLC UV-Vis (Dionex ultimate 3000). Our results indicated that the AgNP’s synthesized showed Absorption spectrum (absorbance peak) at about 400 nm, which confirmed the formation of AgNP’s. The average size and zeta potential analyzed by dynamic light scattering techniques (DLS) showed the sized to be 132.6 nm and the Zeta potential as -ve 13.6 mV suggesting higher stability of AgNP’s. Treatment of water samples with AgNP’s of AI at 10 ppm concentration by conventional incubation method resulted in changes in the peak areas (Peak area directly proportional to the amount present) on the chromatograph from HPLC analysis. Among the selected hormonal compounds, there is a huge reduction of peak areas in the 1 ppm and 5 ppm Diethylstilbestrol (Rt =10.6) by 36.68% and 15.46%; D-Norgestrol (Rt = 11.6) by 7.97% and 27.95%; 19-Norethindrone (Rt = 8.5) by 10.17% and 0.64%; respectively. There was peak reduction observed for 5 ppm of 17-α ethynyl estradiol (Rt = 8.6) by 2.33%, 1 ppm β-Estradiol (Rt= 7.6) by 10.35 % and Estrone (Rt= 9.4) by 6.47 %. These results indicate that we successfully synthesized AgNP-conjugated to herbal plant extract of AI with characteristics consistent with synthesis of nanoparticles. We also successfully demonstrated the ability of the synthesized nanoparticle conjugated herbal extract to remove trace level of hormonal compounds from water. This is a novel effort that need further investigation for broader application in water treatment processes to remove contaminants and in environmental bioremediation.