The objective of this work was to study the adsorption efficiency of bamboo and its surface modified with manganese oxide for removal of Pb(II) ion. The adsorption of Pb(II) from aqueous solution onto bamboo (BB) and manganese oxide-modified bamboo powder (MnO-BB) was evaluated based on batch experiment. The adsorption efficiency of MnO-BB onto Pb(II) was investigated as a function of the initial pH of 6 equilibrium time of 30 min adsorbent concentration of 5 g/L and initial concentration of Pb(II) solution in the range of 50-500 mg/L. The adsorption isotherms of Langmuir Freundlich and Dubinin-Radushkevich were used to describe the equilibrium isotherm. It is observed that the data from MnO-BB adsorbents fitted well to the Langmuir isotherm. The maximum monolayer adsorption capacities of MnO-NC were estimated as 38.76 mg/g. By comparing with BB the amount of Pb(II) adsorbed onto MnO-BB was more than BB by about 40 times under the optimized adsorption condition. According to Dubinin-Radushkevich isotherm the adsorptive mechanism of Pb(II) onto MnO-BB was chemisorption. The kinetic studies of Pb(II) demonstrated that the adsorption of Pb(II) onto MnO-BB adsorbent followed a pseudo second-order model with a good correlation. The adsorption mechanism was processed via chemical ion exchange between H+ and bonded MnO groups and Pb(II) ions in solution

The research aimed to analyze and compare contents of accumulated residue of chlorpyrifos chromium lead and cadmium in five varieties of vegetables in Loei River Loei Province. Five varieties of vegetables such as Vegetable fern (Diplazium esculentum Limnocharis flava (L.)) Limnocharis flava (L.) Buch Lasia spinosa (L.) Thwaites swamp cabbge (Ipomoea aquatica Forsk) and water mimosa (Neptunia oleracea Lour.) were collected during winter summer and rainy seasons from Phu Luang Mueang Loei and Chiang Khan District. Chlorpyrifos was analyzed by high performance liquid chromatography (HPLC). The results showed that the highest chlorpyrifos contents were found in vegetables in winter and summer season in the amount of 0.04±0.00 mg/kg. Analysis of all three heavy metals were carried out dry ashing at 500C and acid digestion with nitric acid prior to analyzing by flame atomic absorption spectrophotometry (FAAS). The results showed that cadmium accumulation in the highest content among all metals in water mimosa (Neptunia oleracea Lour.) in summer season from Phu Luang District (1.83±0.01 mg/kg). The second highest metal content was lead which has found in swamp cabbge (Ipomoea aquatica Forsk) in summer from Mueang Loei District (1.40±0.08 mg/kg). chromium showed the lowest content in Limnocharis flava (L.) Buch in winter from Mueang Loei District (0.47±0.04 mg/kg). The contents of chlorpyrifos and heavy metals were not exceed the legal limits set by International Standard Food and Ministry of Republic Health No.98 of Thailand except Ipomoea aquatica Forsk which collected in summer that showed the lead content higher than the legal limits.

An ability of fresh banana peel without surface modification was evaluated for the removal of lead ions from aqueous solution. Batch adsorption was performed at room temperature. The experimental conditions including dosage contact time initial concentration of lead( II) ion were studied. The characterization of fresh banana peel was carried out by Fourier-transform infrared spectroscopy (FTIR) and energy dispersive X-ray fluorescence ( ED-XRF) . The isotherm models of Langmuir and Freundlich were used to describe the adsorption mechanism involving the relationship between adsorbent surface capacity and adsorbed degree of lead(II)ion in the equilibrium conditions. The experimental data fitted well to the Langmuir isotherm with a correlation coefficient of r2 greater than 0.86. The Maximum adsorption capacity (qm) was found to be 0.9151 mg/g. The results of ED-XRF of fresh banana peels before and after treatment with lead( II) ion confirmed that lead( II) ion was occupied onto the surface of fresh banana peel. Moreover the inside of fresh banana peels was found the lead(II)ion larger than the outside peels. It was concluded that waste of banana could be used as a low-cost adsorbent for removal of lead(II)ion from aqueous solution based on a simple adsorption method.

The purpose of this research is to study the heavy metal removal from wastewater from laboratory by using adsorption process with firebricks. Waste water was collected among three courses of laboratory such as analytical chemistry principle chemistry and chemistry for engineers. The optimized absorption efficiencies of multi-elements with stirring time volume ratio and temperature were 2 hours 10 g/100 mL and room temperature respectively. It was found that absorption efficiencies of lead (Pb) copper (Cu) zinc (Zn) chromium (Cr) were 65.1 54.8 63.4% and ND respectively.