Removal of lead ions (Pb2+) from water and wastewater: a review on the low-cost adsorbents

Abstract

The presence of lead compounds in the environment is an issue. In particular, supply water consumption has been reported to be a significant source of human exposure to lead compounds, which can pose an elevated risk to humans. Due to its toxicity, the International Agency for Research on Cancer and the US Environmental Protection Agency (USEPA) have classified lead (Pb) and its compounds as probable human carcinogens. The European Community Directive and World Health Organization have set the maximum acceptable lead limits in tap water as 10 µg/L. The USEPA has a guideline value of 15 µg/L in drinking water. Removal of lead ions from water and wastewater is of great importance from regulatory and health perspectives. To date, several hundred publications have been reported on the removal of lead ions from an aqueous solution. This study reviewed the research findings on the low-cost removal of lead ions using different types of adsorbents. The research achievements to date and the limitations were investigated. Different types of adsorbents were compared with respect to adsorption capacity, removal performances, sorbent dose, optimum pH, temperature, initial concentration, and contact time. The best adsorbents and the scopes of improvements were identified. The adsorption capacity of natural materials, industrial byproducts, agricultural waste, forest waste, and biotechnology-based adsorbents were in the ranges of 0.8–333.3 mg/g, 2.5–524.0 mg/g, 0.7–2079 mg/g, 0.4–769.2 mg/g, and 7.6–526.0 mg/g, respectively. The removal efficiency for these adsorbents was in the range of 13.6–100%. Future research to improve these adsorbents might assist in developing low-cost adsorbents for mass-scale applications.

Rapid and Effective Lead Elimination Using Cow Manure Derived Biochar: Balance between Inherent Phosphorus Release and Pollutants Immobilization

“…For CM400 and CM600, the pseudo-second-order kinetic model fitted the adsorptions better (0.9997 and 0.9998 vs. 0.9999 and 0.9999), by contrast, for CM800, the pseudo-first-order kinetic model described the adsorption slightly more accurately (0.9998 vs. 0.9988). Therefore, physisorption and chemisorption likely coexisted during adsorption by CM400 and CM600, while physisorption dominated Pb(II) adsorption by CM800 [ 39 ]. Physisorption was reversible and slow [ 1 ], which can be verified by the lower Q e of CM800 than that of CM400 (98.21 vs. 81.28 mg·g −1 ).…”

Chemical Modification of Neem (Azadirachta indica) Biomass as Bioadsorbent for Removal of Pb2+ Ion from Aqueous Waste Water

“…The batch adsorption experiments were carried out at various pH solutions. Due to precipitation of Pb(OH) 2 , the adsorption of Pb 2+ ion does not take place beyond solution pH of 7.0 [43][44][45][46]. Therefore, in the present work, the bioadsorption experiments were performed at various pH which are below pH of 7.0 by adding the required volumes of 0.1 M of HCl or 0.1 M of NaOH solution.…”

Synthesis and Characterization of Novel Thiosalicylate-based Solid-Supported Ionic Liquid for Removal of Pb(II) Ions from Aqueous Solution

“…The problems associated with the usage of volatile organic solvents in liquid–liquid extraction have motivated many researchers to find alternative metal extractants that would be efficient, cost effective, and environmentally friendly. One of the alternatives that is being extensively studied by researchers to replace organic solvents as metal extractants in liquid–liquid extraction is ionic liquids (ILs) [ 11 ].…”

“…The [MTMSPI][TS] ionic liquid containing the thiosalicylate functional group was chosen to be chemically immobilized on activated silica gel in SSIL (as an extraction agent for Pb(II) ions from aqueous solution) because of the high affinity of thiosalicylate towards metal ions [ 21 ]. Meanwhile, Pb(II) ions have been selected as this metal ion is commonly found in industrial wastewater [ 11 ]. The kinetics studies for the removal of Pb(II) ions was carried out at different contact times (2–250 min).…”