Adsorption Removal of 17β-Estradiol from Water by Rice Straw-Derived Biochar with Special Attention to Pyrolysis Temperature and Background Chemistry.

Xiaohua Wang,Zhihong Yin,Jiang Li,Sirong Tian,Shaobo Liu,Guangming Zeng,Luhua Jiang,Xiaofei Tan,Yunguo Liu,Ni Liu

doi:10.3390/ijerph14101213

Abstract

Rice straw biochar that produced at three pyrolysis temperatures (400, 500 and 600 °C) were used to investigate the adsorption properties of 17β-estradiol (E2). The biochar samples were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), elemental analysis and BET surface area measurements. The influences of pyrolysis temperature, E2 concentration, pH, ionic strength, background electrolyte and humic acid were studied. Kinetic and isotherm results illustrated that the adsorption process could be well described by pseudo-second-order and Freundlich models. Experimental results showed that ionic strength had less influence on the adsorption of E2 by 500 and 600 °C rice straw biochar. Further, multivalent ions had positive impact on E2 removal than monovalent ions and the influence of the pyrolysis temperature was unremarkable when background electrolyte existed in solutions. The adsorption capacity of E2 decreased with the pH ranged from 3.0 to 12.0 and the humic acid concentration from 2 to 10 mg L−1. Electrostatic attractions and π-π interaction were involved in the adsorption mechanisms. Compared to low-temperature biochar, high-temperature biochar exhibited a better adsorption capacity for E2 in aqueous solution, indicated it had a greater potential for E2 pollution control.

Highlights

As early as in 1993, the paper “Estrogen as an Environment Pollutant” had suggested that hormones excreted into the environment by humans and animals were present in sufficient quantities to disrupt the environment [1]
Sangeeta et al used bone char derived from waste cattle bones to remove E2 from aqueous solutions and the results showed that the adsorption efficiency reached to 95.3% with a bone char dosage of 50 g L−1 [25]
Images (Figure S1), the morphology changes as pyrolysis temperature increased

Summary

Introduction

As early as in 1993, the paper “Estrogen as an Environment Pollutant” had suggested that hormones excreted into the environment by humans and animals were present in sufficient quantities to disrupt the environment [1]. The related research about the endocrine disrupting compounds (EDCs, i.e., environmental hormone) pollution has caused the extensive concern. EDCs is a kind of chemicals that may disrupt the endocrine systems of animals and humans through mimicking natural hormones, inhibiting the action of hormones, or alter the normal regulatory function of the immune nervous and endocrine systems [2]. As a common of EDCs, 17β-estradiol (E2) was detected in water. Res. Public Health 2017, 14, 1213; doi:10.3390/ijerph14101213 www.mdpi.com/journal/ijerph

Methods

Results

Conclusion