In vitro, in vivo studies of Cu(II)-exchanged montmorillonite for the removal of lead (Pb)

Highly porous carboxylated activated carbon from jute stick for removal of Pb2+ from aqueous solution

Drinking water is a potential source of human exposure to lead (Pb²⁺), which can induce several health effects upon exposure to low dose for a long period. In particular, the children and young populations are the vulnerable groups. Removal of Pb²⁺ from drinking water using an inexpensive adsorbent is a challenge. In this research, activated carbon adsorbent was developed using jute stick, an agricultural by-product. Following carboxylic acid functionalization, the jute stick activated carbon (JSAC) was applied for Pb²⁺ removal from aqueous solution. The carboxylated JSAC (JSAC-COO^-) was characterized using several techniques. The surface area of the JSAC-COO^- was 615.3 m²/g. The JSAC-COO^- was tested for variable concentrations of Pb²⁺ (10 and 25 mg/L) at different pH (4.0 and 7.0), temperature (15 °C and 27 °C), and contact periods (1, 5, 10, 15, 30, and 60 min). Up to 99.8% removal of Pb²⁺ was achieved for these concentrations of Pb²⁺ within 15 min of contact time. The adsorption process followed standard kinetics, and the adsorption capacity was > 25.0 mg Pb²⁺/g of JSAC-COO^-. The JSAC-COO^- can be used for fast and easy removal of Pb²⁺ from aqueous solution, which has the potential for domestic and industrial applications.

Ag-carried CMC/functional copolymer/ODA-Mt wLED-treated NC and their responses to brain cancer cells

The subject of this work is synthesis and characterization of novel multifunctional nanocomposite (8/2A-NC) consisting (1) carboxymethyl cellulose (CMC) as a matrix biopolymer and poly (maleic acid-alt-acrylic acid) as a reactive synthetic partner matrix polymer; (2) octadecyl amine montmorillonite (ODA-MMT) reactive organoclay provide intercalated silicate layers structures and aqueous colloidal dispersing medium, and MMT as carriers and targeting agents for anticancer agents in drug delivery systems, respectively. ODA as a intercalated surfactant finely dispersed 8/2A NC and its compatibility with matrix polymers via the interfacial polarization (complexing) and functionalization of matrix polymers by amine (ODA) and carboxylic acids from both the CMC and copolymer; (3) silver nanoparticles (AgNPs) as in-situ generated onto matrix polymers with unique nano-size and morphology parameters was synthesized. Important material science and bioengineering aspects of these investigations included (a) novel approach in synthetic pathways; (b) effects of physical and chemical structural rearrangements; (c) effects of Light Emitting Dioda (LED)-treatment on the FT-IR spectra, XRD reflection parameters, SEM-TEM morphology and nano-size and diameter distribution of AgNPs onto matrix polymers; (d) positive effect of LED-treatment of 8/2A nanocomposite and its response to the MIAPaCa-2 and U87 human brain cancer cell lines were evaluated. Novel 8/2A-NC multifunctional drug consisting unique positive, intercalating and encapsulated core-shell morphology structures, nano-size (5.6 nm) and narrow diameter distribution (94%) of AgNPs onto matrix polymers [silver NPs (0.25%) in 8/2A NC (25%)] with highest volume of contact area compared with used cancer micro-cells show lowest cell viability as an excellent anticancer platform. 8/2A-NC is a novel multifunctional drug with intercalating and encapsulated core-shell morphology structures consisting of positively charged, non-randomly distributed AgNPs with a large contact area and low diameters (5-6 nm). The anticancer properties of (This factor is not conformed experimentally in work) this drug can be explained by the following structural factors: 8/2A-NC contains a combination of active sites from protonated hydroxyl, carboxyl and amine groups; Ag⁺-cations and ODA-MMT with high physical and chemical surface areas. We suggest this material be further explored for anti-cancer testing.

Evaluation of Dietary Palygorskite Supplementation on Growth Performance, Mineral Accumulations, Antioxidant Capacities, and Meat Quality of Broilers Fed Lead-Contaminated Diet

The objective of this study was to evaluate influence of dietary palygorskite (Pal) supplementation on growth performance, mineral accumulations in the tissues (livers, kidneys, and muscles), antioxidant capacities, and meat quality of broilers fed lead (Pb)-contaminated diet. One-hundred forty-four male broiler chicks were randomly divided into three treatment groups, receiving a corn-soybean meal basal diet (the control group), the basal diet contaminated with 10 mg/kg Pb (the Pb group), and the basal diet with 10-g/kg Pal supplementation and 10-mg/kg Pb contamination (the Pal/Pb group) from 1 to 42 days of age, respectively. Treatments did not affect growth performance of broilers in the 42-day study (P > 0.05). Compared with the control group, Pb contamination increased Pb accumulation in the livers, kidneys, and muscles (P < 0.05); elevated malondialdehyde accumulation in the livers, kidneys, and breast muscles; glutathione peroxidase activity in the livers and superoxide dismutase activity in the kidneys (P < 0.05); exacerbated drip loss in the pectoralis muscles (P < 0.05); and reduced glutathione peroxidase activity in the pectoralis muscles (P < 0.05) of broilers at 42 days of age. The values of these parameters were reversed in the Pal/Pb group to levels comparable with those in the control group (P < 0.05). Additionally, Pal supplementation reduced redness value in the pectoralis muscles (P < 0.05), and decreased Cu concentration in the pectoralis muscles and livers at 42 days of age as well as its accumulation in the kidneys at both 21 and 42 days of age compared with the other two groups (P < 0.05). The results suggested that dietary Pal supplementation would decrease Pb residue in the tissues, alleviate oxidative stress, and affect meat quality of broilers exposed to Pb.

Characterization and lead adsorption properties of activated carbons prepared from cotton stalk by one-step H3PO4 activation

Activated carbons were prepared from cotton stalk by one-step H(3)PO(4) activation and used as adsorbent for the removal of lead(II). Taguchi experimental design method was used to optimize the preparation of the adsorbents. The results showed that the optimized conditions were: impregnation with a 50% (w/v) phosphoric acid solution with a mass ratio of 3:2 and activation temperature at 500 degrees C for 60 min with the rate of achieving the activation temperature equal to 10 degrees C min(-1). The cotton stalk activated carbon (CSAC) prepared at these conditions have 1.43 mmol g(-1) acidic surface groups and 1570 m(2) g(-1) BET surface area. Adsorption isotherms for lead(II) on the adsorbents were measured by conducting a series of batch adsorption experiments. The Langmuir maximum adsorption amount of lead(II) on CSAC was more than 119 mg g(-1), which was superior to the ordinary commercial activated carbon (CAC) on the market. Compared with the CAC, the CSAC had a wider applicable pH range from 3.5 to 6.5 for lead(II) uptake. The final pH values at equilibrium after adsorption were lower than the initial pH value, indicating that the ion-exchange process was involved in the adsorption. This is also confirmed by the result that the increase of acidic surface groups favored the adsorption process. Thermodynamic study indicated that the adsorption was a spontaneous and endothermic process.

Mechanism and kinetics of Pb(II) adsorption on ultrathin nanocrystalline titania coatings

Pb(II) is a highly toxic substance, exposure to which can cause various diseases. To better understand the application of titania as an adsorbent for removing Pb(II) from wastewater, quartz crystal microbalance (QCM) technique was employed to investigate the adsorption behavior of Pb(II) on ultrathin nanocrystalline titania coatings. The present study focused on the mechanism and kinetics of Pb(II) adsorption. The obtained results show that the driving force of Pb(II) adsorption on titania coatings is electrostatic interaction, and that Pb(II) is adsorbed onto titania coatings by Pb(II) ions coordinating with hydroxyl groups of titania surface. In terms of the in situ frequency measurements of QCM, the adsorption kinetic parameter is estimated to be 4.12x10(5)L/mol. QCM measurement provides a useful method for monitoring the adsorption process of Pb(II) on titania coatings.

Adsorptive removal of Pb(II) by activated carbon prepared from Spartina alterniflora: equilibrium, kinetics and thermodynamics

Low-cost activated carbon was prepared from Spartina alterniflora by phosphoric acid activation for the removal of Pb(II) from dilute aqueous solution. The effect of experimental parameters such as pH, initial concentration, contact time and temperature on the adsorption was studied. The obtained data were fitted with the Langmuir and Freundlich equations to describe the equilibrium isotherms. The kinetic data were fitted with the Lagergren-first-order, pseudo-second-order and Elovich models. It was found that pH played a major role in the adsorption process. The maximum adsorption capacity for Pb(II) on S. alterniflora activated carbon (SAAC) calculated from Langmuir isotherm was more than 99 mg g(-1). The optimum pH range for the removal of Pb(II) was 4.8-5.6. The Freundlich isotherm model was found to best describe the experimental data. The kinetic rates were best fitted to the pseudo-second-order model. Thermodynamic study showed the adsorption was a spontaneous exothermic process.