Papers by Keyword: Lead

Abstract: This study explored the feasibility of removing nickel (Ni) and Pb (II) from water solutions using the adsorption technique by cellulose recovered from office paper waste. Metal removal is required to reduce the direct or indirect exposure of industrial waste to the environment, due to its potential for harm to human health and ecosystems. The release criterion is maintained to keep the efficient wastewater treatment of the metals of concern, which are toxic to both humans and other organisms. The cellulose was first prepared from office paper waste. The removal values can be rationalized as follows: Lead removal efficiencies of were obtained upto %95.0632, while the removals of nickel were obtained as 54.3866%. The adsorption process was effective with the initial metal concentration and the adsorbent dose used. In addition, the study focused on the competition between the adsorption of lead and nickel ions, which inhibited their removal in a mixture. To sum up, in the present study, the prospects of removing heavy metals by low-cost renewable materials are demonstrated, and in general, those concerning the protection of the environment and the minimization of waste.

Abstract: Lead hydroxyapatite (PbHAP, chemical formula Pb₁₀(PO₄)₆(OH)₂) has been synthesized by ceramic (solid-state reaction) and semi-ceramic (precipitation) methods. The samples were prepared through a solid-state reaction conducted at 830 °C for 60 hours, with the y values ranging from 0.95 to 1.00. We have developed and created the most efficient preparation methods. The well-known technique was used - semi-ceramic (precipitation) deposition of lead and hydroxyapatite. For this purpose, several advanced devices were used to obtain an accurate structural structure of lead hydroxyapatite compounds. It has been observed, as in the case of chemical synthesis, that the elements (lead, phosphorus, and oxygen) appear to be distributed homogeneously within the crystals, regardless of the method of composition, which indicates that the samples are homogeneous. More importantly, the "solid-state reaction" method favored a specific composition range, while the "precipitation" method performed well for other composition ranges. The above methods indicate an ideal method, according to the desired structure, that should be developed for lead hydroxyapatite, depending on its composition. This research aims to establish the first steps in developing a new method for preparing lead hydroxyapatite compounds with the desired properties to improve their purity and crystal structure for potential uses in the future.

Abstract: Clarifying the distribution of cadmium (Cd) and lead (Pb) in the soil of Hainan's Se-rich areas will not only provide a basis for the healthy and sustainable development of Hainan's Se-rich industry, but also provide ideas for Hainan's agricultural and food safety research. Using a method that combines field investigation and indoor analysis, with the help of geostatistics and spatial analysis technology, the concentration of Pb and Cd in the soil and rice in the area were studied. The Cd in the cultivated soil layer of the arableland in the area is lower than the first-level standard of our country's soil environmental quality standards, and the soil Pb content is slightly higher than the first-level standard. The overall ecological risk is low. Pb and Cd in polished rice are 0.14 and 0.11 mg/kg respectively. The concentrations distribution of lead and cadmium in rice is: straw > polished rice. Heavy metals are more likely to accumulate in non-edible parts such as straw.

Abstract: Modification of activated carbon using chemical surfactant is not eco sustainable because the chemical will have the potential to desorb into aqueous medium. Due to the environmental concerns, this research aims to investigate the usage of plant-based surfactant as a modifying agent onto the surface of activated carbon (AC) to be used in the removal of lead from aqueous solution. AC was impregnated with sodium lauryl sulfoacetate (SLSA), a plant based anionic surfactant at different concentrations. Atomic absorption spectroscopy (AAS) was used to examine the percentage removal of lead and to identify the effect of pH on the adsorptive properties of SIAC. The results exhibited the enhancement in the adsorption of lead using modified AC with SLSA. It was found that SIAC at 25 mg/L has the highest lead removal which was 99%. The optimum concentration anionic surfactant obtained was used in parametric study effect of pH. The optimum pH was obtained at pH 6 as it indicated the highest removal of lead (84.92%). Excel software was used to fit the data using polynomial regression. R² and adjusted R derived from the analysis were 0.9043 and 0.9522, respectively. As a result of the ANOVA study, it was shown that the mathematical formula can be utilised to forecast the removal of lead from aqueous solution.

Abstract: This study aims to determine the optimal conditions of acid-activated clay adsorbent in adsorption of Pb²⁺ metal ions. Clay was taken around East Kalimantan, Karang Joang. This adsorbent was prepared by mixing clay into a solution of KMnO₄, H₂SO₄ and HCl successively, and stirred for 4 hours at a temperature of 80°C. The morphology and active groups of the adsorbent were analyzed using BET and FTIR. The variables of this study were the mass of the adsorbent 0.1, 0.3 and 0.5 grams and the contact time of 5, 30 and 55 minutes. Adsorption capacity of this adsorbent was analyzed using Atomic Absorption Spectrophotometry (AAS). The results of this study indicate that the optimum mass of adsorbent is 0.1 g, and contact time is 30 minutes. Adsorption capacity of Pb²⁺ metal ions by acid-activated clay adsorbent at the optimum condition of 0.1 gram was 23,585 mg/g and adsorption energy was 2,338 kJ/mol. Meanwhile, at the optimum condition for 30 minutes, the adsorption capacity was 0.771 mg/L, and the adsorption energy was 2.895 kJ/mol. So that the adsorption process in this study can be known, namely physical adsorption because the adsorption energy value is less than 40 kJ/mol.

Abstract: Water contamination by heavy metals is one of the most serious environmental problems and harms human life. Numerous nanotechnologies have been utilized to overcome this problem so far. Herein, we introduce lignin/polyacrylonitrile (PAN) composite nanofibers prepared via electrospinning for the removal of lead from aqueous solution. The effects of blend ratios between lignin and PAN concentration (LP) were investigated. The performance of adsorption process depends on the following parameters including contact time of adsorbent and adsorbate (equilibrium times: after 16 h. for 10 mg/L of lead concentration), types of nanofibers (LP55 at 1 g/L), and the percentage of lead removal was 72.5 % within 24 hours by LP55 nanofibers. The highest correlation coefficients were performed for the pseudo-second order kinetic model both LP55 and PAN nanofibers. This study demonstrates that the potential of the biomass-derived material with nanotechnology for environmental remediation.

Abstract: Waelz-oxide is a raw material for the production of metallic zinc. Waelz-oxide contains impurities of zinc and lead chlorides and fluorides. Halides have a negative effect on the process of zinc electrolysis. Halides have a relatively low boiling point; therefore, they are removed into the gas phase by calcining Waelz-oxide at 800–850 °С. To intensify the process, calcination is sometimes carried out at elevated temperatures of 1100–1250 °С. However, an increase in temperature leads to partial melting and granulation of the calcined product. In the present work, the chemical and phase composition of the initial and calcined Waelz-oxide was studied. Thermodynamic modeling of phase and chemical transformations of Waelz-oxide components during heating has been performed. Experiments on calcination of Waelz-oxide in laboratory conditions at temperatures of 600–1250 °C were carried out. It was found that partial melting and granulation of Waelz-oxide is the result of the formation of fusible eutectics containing lead oxide. Lead oxide is formed as a result of decomposition of lead sulfate when heated above 1100 °C. A similar effect is not observed at a standard calcination temperature of 850 °C.

Abstract: Studies have been conducted to assess the possibility of refining a lead collector containing precious metals, with the aim of obtaining lead using an economically viable technology. Studied the patterns of anodic oxidation of lead and impurities in alkaline-water-glycerate electrolytes, depending on the concentration of sodium hydroxide and glycerol in the electrolyte, the potential sweep rate.

Abstract: Adsorption of Pb(II) ions onto selective adsorbent of dithizone-immobilized coal fly ash (DCFA) from Holcim, Cilacap, Indonesia has been investigated in batch experiments. Prepared coal fly ash (CFA) modified by immobilization of dithizone previously were characterized by FT-IR and XRD. Several parameters influencing the adsorption of Pb(II) ions such as effect of pH, adsorbent dosage, contact time and initial concentration of ions on the efficiency of the adsorption were studied. The optimum condition of Pb(II) adsorption was found at pH 5, adsorbent dosage 0.1 g, contact time 60 min and initial Pb(II) ions concentration of 60 mg L^–1. The adsorption kinetics of Pb(II) ions on DCFA was found to follow a pseudo-second-order kinetic model. The adsorption isotherm data were fitted to the Langmuir model. Kinetics and adsorption isotherm studies suggest that the capacity and affinity of the DCFA in adsorbing Pb(II) ions is significantly improved compared to those of non-immobilized activated coal fly ash (ACFA).

Abstract: This work studied the potentials of indigenous Micrococcus sp., Bacillus sp., Pseudomonas sp., and Escherichia coli (E. coli) for bioremediation of lead contaminated soils collected from Amita forest in Ebonyi State of Nigeria.The organisms isolated from the soils were conditioned with the predetermined optimum factors in inoculated soil samples. The samples were tested for residual lead concentration at times 8, 16, 24, 32, 40, 48, and 56 days with Atomic Absorption Spectrophotometer.The performances of the organisms were in the decreasing order of Micrococcus sp., Bacillus sp., Pseudomonas sp., and E. coli. Micrococcus sp. and Bacillus sp. performed earlier at time 16 days as against Pseudomonas sp., and E. coli at 24 days. The maximum efficiencies were discovered at time 56 days as 76.68%, 72.24%, 70.11% and 55.47% for Micrococcus sp., Bacillus sp., Pseudomonas sp., and E. coli respectively with respective residual concentrations of 31.55 mg/kg, 37.55 mg/kg, 40.44 mg/kg and 60.24 mg/kg at the respective efficiencies.The rates of removals were in the decreasing order of -0.0524d^-1 for Pseudomonas sp., -0.0714 d^-1 for Bacillus sp., -0.0743d^-1 Micrococcus sp., and 0.113 d^-1 E. coli. The fitted models showed diffusion as the rate-limiting step for removals by Pseudomonas sp., Bacillus sp., and Micrococcus sp.; while chemisorption was the rate-limiting step for removal by E. coli. This information will be helpful to researchers and decision makers for the remediation of lead contaminated soils.