Highly enhanced adsorption for decontamination of lead ions from battery wastewaters using chitosan functionalized with xanthate

Microwave induced β-cyclodextrin modification of chitosan for lead sorption

“…It was likely that both the electrostatic and complexation reactions occurred between the sorbent and the metal ion; therefore, complete desorption was not possible. This observation was similar to earlier reports [27,32] where the percent adsorbed reduced in subsequent cycles.…”

“…In a certain pH range for Pb(II) here may be number of species present in solution, such as Pb 2+ , Pb(OH) + , Pb(OH) 2 , etc. At lower pH, the positive charged lead ion species may compete with H + and be adsorbed at the surface of the Ch-g-␤-CD by ion exchange mechanism [27]. An increase in pH shows an increase in adsorption up to 4.5 in which the surface of Ch-g-␤-CD is negatively charged and the adsorbate species are also still positively charged.…”

Removal of mercury and methylene blue from aqueous solution by xanthate functionalized magnetic graphene oxide: Sorption kinetic and uptake mechanism

“…The FTIR spectrum of Fe 3 O 4 -GO demonstrated the presence of CAO at 1118 cm À1 , CAOH at 1384 cm À1 , C@O in carboxylic acid and carbonyl moieties at 1628 cm À1 and 1737 cm À1 [43]. Absorption peaks appeared at 1573 cm À1 of Fe 3 O 4 -xGO corresponding to the C@S stretching vibration of the xanthate unit and the diminution of the hydroxyl peak (1384 cm À1 ) after xanthation were strong indicative of the presence of xanthate group bonded to the charred materials [8]. 1 1) and (4 0 0) appeared [44].…”

“…There are two possible explanations for the low adsorption at low pH. First, the xanthate group is known to be unstable in strong acid solution and to be able to dissociate from the graphene back bone [8]. Decomposition is a twostage process in which the first is the protonation of the hydroxyl group and the second is the elimination of carbon disulfide as shown in Fig.…”

“…As one of most common contaminant of heavy metals, mercury ions in drinking water are from erosion of natural deposits, discharge from refineries or factories and runoff from landfills or croplands, which may cause kidney damage from long-term exposure. Due to its toxicity, the US Environmental Protection Agency (EPA) has set the maximum contaminant level (MCL) of mercury ions in drinking water to be 0.002 mg/L (Primary Drinking Water Rules, 2009) [8]. For dyes, even a small amount in natural water bodies is likely to bring about a serious environmental problem, since these substances can affect the photosynthesis of aquatic life deleteriously due to its highly obvious color to water which could reduce light penetration [9][10][11][12].…”