Removal of Pb, Zn, and Cd from contaminated soil by new washing agent from plant material

Abstract

Soil washing is an effective approach to remove soil heavy metals, and the washing agent is generally regarded as one of the primary factors in the process, but there is still a lack of efficient and eco-friendly agents for this technique. Here, we showed that four plant washing agents-from water extracts of Coriaria nepalensis (CN), Clematis brevicaudata (CB), Pistacia weinmannifolia (PW), and Ricinus communis (RC)-could be feasible agents for the removal of soil lead (Pb), zinc (Zn), and cadmium (Cd). The metal removal efficiencies of the agents increased with their concentrations from 20 to 80 g L, decreased with the increasing solution pH, and presented different trends with the reaction time increasing. CN among the four agents had the highest removal efficiencies of soil Pb (62.02%) and Zn (29.18%) but owned the relatively low Cd removal efficiencies (21.59%). The Fourier transform infrared spectroscopy showed that the abilities of plant washing agents for the removal of soil heavy metals may result from bioactive substances with specific functional groups such as -COOH, -NH, and -OH. Our study provided CN as the best washing agents for the remediation of contaminated soil by heavy metals.

A review of green remediation strategies for heavy metal contaminated soil

“…humic substances) (Kulikowska et al, 2015;Meng et al, 2017), biodegradable chelants (e.g. imminodisuccinic acid, methylglycinediacetic acid, citric acid and poly-γ-glutamic acid) (Begum et al, 2012;Guo et al, 2018), plant-derived washing agents (Cao et al, 2017a(Cao et al, , 2017b) and biosurfactants (Singh & Cameotra, 2013) have emerged as novel extractants in the soil washing process. To date, the applicability of these novel extractants has only been tested in the laboratory.…”

Simultaneous removal of multiple heavy metals from soil by washing with citric acid and ferric chloride

“…In addition, FTIR analysis was used to identify the functional groups of the soil. 57 Hydroxyl and carboxyl groups were proven to be important in the adsorption of heavy metals in soil. 58 In this study, the disappearance of carboxylic groups (1427 cm À1 ) and hydroxyl groups (1036 cm À1 ) illustrated the dissolution of organic matter aer washing (Fig.…”

Washing agents from sewage sludge: efficiency of Cd removal from highly contaminated soils and effect on soil organic balance

“…Hong et al (2002), who used the Tessier fractionation procedure, found that saponin removed 83% of Cd from the exchangeable and carbonate fractions (equivalent to F1 fraction in the present study), and 33% of Cd from the Fe-Mn oxide fraction, but had little effect on the content of Cd in the organic fraction. Cao et al (2017) found that an aqueous extract from Coriaria nepalensis, Clematis brevicaudata, Pistacia weinmannifolia, and Ricinus communis plants at pH 4 was only able to decrease the Cd concentration in F1 fraction.…”