Experimental Study on Cr6+ Adsorption in Water about the Daily Waste Peanut Shell

2013 ◽  
Vol 690-693 ◽  
pp. 1003-1007
Author(s):  
Chao Jin Wang ◽  
Tai Hang Li ◽  
Ling Lu Tang ◽  
Zhou Zou ◽  
Wen Ji Liu ◽  
...  

The peanut shell was used as the adsorbent of Cr6+ in this paper. A series experiences have been discussed and studied through the following three aspects, which were the adsorption time, modification effect and contact area. The results showed that the peanut shell for the removal rate of Cr6+ presented increasing tendency over time. In condition of 25°C, 1.0g unmodified peanut shell,50mL 30mg·L-1 Cr6+ solution, the initial pH value 1.0 and contact time 300min, the adsorption rate of Cr6+ was only 71%. In the same conditions, the removal rate of modified peanut shell was 75%, compared to the unmodified increasing by 4%. Thus modified treatment for peanut shell has no significant effect on the adsorption effect. And In condition of 25°C, 50mL 30mg·L-1 Cr6+ solution, the initial pH value 1.0 and contact time 270min, the removal rate of 1.0g modified peanut shell was 75%, but the modified peanut shell powders removal rate was 99%, representing an increase of 25% before crushing, thus to increase the contact area can improve the adsorption effect.

2011 ◽  
Vol 71-78 ◽  
pp. 3029-3032 ◽  
Author(s):  
Xin Zhao ◽  
Chao Yu Hu ◽  
Xu Yan

In order to investigate the adsorption of hexavalent chrome in wastewater by peanut shell, the orthogonal test was designed to find the best adsorption conditions such as pH value, temperature, adsorption time and adsorbent dosage etc. The results show that the peanut shell is a kind of economic and efficient absorbent; hexavalent chrome removal rate can reach more than 85%, when the hexavalent chrome wastewater concentration is 30mg/L, dosing 1g peanut shells into 50mg wastewater, adjusting pH value to 2.0, adsorbing 300min at room temperature.


2013 ◽  
Vol 726-731 ◽  
pp. 2687-2690
Author(s):  
Qian Cheng ◽  
Xing Yong Liu ◽  
Min Li

With the development of the biogas construction, a plenty of biogas slurry was generated. It brought destruction to the environment for the biogas slurry was rich in nutrient components, especially ammonia-nitrogen. Its important that biogas slurry should be treated before it returns to the environment. The zeolite is extensively used in ammonia-nitrogen adsorption for its good adsorption effect. In this study, a modified coal fly ash (CFA) which was produced from raw CFA and had similar structure with zeolite was used as the adsorbent to adsorb ammonia-nitrogen in biogas slurry. The optimum adsorption conditions of modified CAF on adsorbing ammonia-nitrogen in biogas slurry were explored. The results showed that the best conditions were: the mass of modified CAF 1.3g, the initial pH value of solution 5~7 and the adsorption time 20 min.


e-Polymers ◽  
2016 ◽  
Vol 16 (2) ◽  
pp. 99-109 ◽  
Author(s):  
Xiu-Juan Wu ◽  
Ji-De Wang ◽  
Li-Qin Cao

AbstractNovel chitosan/diatomite (CS/DM) membranes were prepared by phase inversion technique to remove anionic azo dyes from wastewater. The fabricated composite membranes exhibited the combined advantages of inorganic substances, diatomites, and polysaccharides. These composite membranes were characterized through Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction analysis. The mechanical properties of the membranes were also evaluated. Adsorption experiments were conducted under varied initial dye concentration, solution pH values, contact time, and adsorbent dosage. The results indicate that pH 3 is the optimal pH value for Orange G adsorption. The CS/DM membranes exhibit the highest adsorption capacity of 588 mg g-1 and removal rate of 94% under an initial dye concentration of 200 mg l-1, contact time of 6 h, and membrane dosage of 8 mg. Langmuir, Freundlich and Redlich-Peterson adsorption models were applied to describe the equilibrium isotherms at different dye concentrations. The equilibrium data was found to be fitted well to the Redlich-Peterson isotherm. Pseudo-first-order and pseudo-second-order kinetics models were used to describe the adsorption of membranes. The adsorption data were well explained by pseudo-second-order models, and also followed by the Elovich model. In addition, these membranes display high adsorption capacity and mechanical performance even after reused for seven times.


2018 ◽  
Vol 77 (5) ◽  
pp. 1363-1371 ◽  
Author(s):  
Yong Fu ◽  
Yue Huang ◽  
Jianshe Hu ◽  
Zhengjie Zhang

Abstract A green functional adsorbent (CAD) was prepared by Schiff base reaction of chitosan and amino-modified diatomite. The morphology, structure and adsorption properties of the CAD were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and Brunauer Emmett Teller measurements. The effect of pH value, contact time and temperature on the adsorption of Hg(II) ions for the CAD is discussed in detail. The experimental results showed that the CAD had a large specific surface area and multifunctional groups such as amino, hydroxyl and Schiff base. The optimum adsorption effect was obtained when the pH value, temperature and contact time were 4, 25 °C and 120 min, respectively, and the corresponding maximum adsorption capacity of Hg(II) ions reached 102 mg/g. Moreover, the adsorption behavior of Hg(II) ions for the CAD followed the pseudo-second-order kinetic model and Langmuir model. The negative ΔG0 and ΔH0 suggested that the adsorption was a spontaneous exothermic process.


1997 ◽  
Vol 36 (2-3) ◽  
pp. 263-270 ◽  
Author(s):  
Cheng-Nan Chang ◽  
Jih-Gaw Lin ◽  
Allen C. Chao ◽  
Bo-Chuan Cho ◽  
Ruey-Fang Yu

Acrylonitrile and styrene are used as the raw materials for manufacturing acrylic fiber, thus they are often found as pollutants in the petrochemical wastewater. This study utilizes ozone to decompose the organic nitrogen contained in acrylonitrile and styrene, and the oxidation process was monitored using on-line measurements of oxidation-reduction potential (ORP) and pH. The efficiency of organic nitrogen decomposition was also estimated based on the COD, organic nitrogen, TOC, ammonia-N, nitrite, and nitrate measurements. Both the initial pH and alkalinity are observed to affect the degradation rate of organic nitrogen. The acrylonitrile sample with the lowest initial pH value (i.e., 4.0) has a shorter t1/2 of 18.9 min and that for samples of the highest initial pH (i.e., 11) was 34 min. The alkalinity of one acrylonitrile sample was boosted by adding 500 mg/l CaCO3, to simulate the field ABS (Acrylonitrile-Butadiene-Styrene) wastewater effluent. It was observed that within a short ozone contact time, the acrylonitrile sample spiked with 500 mg/l CaCO3 had the highest COD decomposition rate of 0.411 min−1, or 1.3 times more than that for samples without addition of CaCO3. Results of the ozonation process can be fitted with a modified Nernst equation for the various pH conditions. Additionally, the ozone treated synthetic ABS sample shows a faster COD removal rate in the subsequent biological process than those samples without ozone treatment.


2011 ◽  
Vol 255-260 ◽  
pp. 2797-2801
Author(s):  
Chen Yao ◽  
Chun Juan Gan ◽  
Jian Zhou

Effect of environment factors such as initial pH value, dissolved oxygen (DO) and temperature on phosphorus removal efficiency of phosphate reduction system was discussed in treating pickled mustard tube wastewater. Results indicate that environment factors have significant influence on dephosphorization efficiency. And, the impact of DO on phosphate reduction is mainly by affecting the distribution of micro-environment inner biofilm, manifest as phosphate removal rate decreased with a fall in DO concentration, while overhigh DO can lead to detachment of biofilm, thus causing the increase of effluent COD concentration, and so DO need to be controlled in the range of 6 mg/L. Moreover, a higher temperature is more beneficial to phosphorus removal by PRB. Unfortunately, exorbitant temperature can result in mass rearing of Leuconostoc characterized with poor flocculability in reactor, and that cause turbidity in effluent appeared as a rise in COD of effluent. Hence, the optimal temperature is found to be about 30°C.


2013 ◽  
Vol 791-793 ◽  
pp. 24-27
Author(s):  
Qing Shan Pan ◽  
Dai Qi Li ◽  
Jian Qiang Li ◽  
Wei Liu ◽  
Mei Gui Ma ◽  
...  

Peanut shell Cellulose Xanthate (PCX) was prepared by reacting with carbon disulphide after mercerized by sodium hydroxide solution. The preparing conditions (hydroxide solution concentration, carbon disulphide dosage, temperature) were optimized in this study. And the effects of PCX amount and contact time on the removal of Cd (II) ion from aqueous solution was studied,the results indicated that when the initial Cd (II) ion concentration was 10mg/L, the adsorption capacity of PXC was high effective with the PCX amount was 1g/L and the contact time was 1.5h,the equilibrium adsorption capacity of PCX was 9.87 mg/g and the removal rate of Cd (II) ion was 98.72%.Then the regeneration capacities of PCX adsorbent was investigated, the results indicated that the removal rate of Cd (II) ion was more than 75% after regeneration. All the results indicated that the PCX can be used as a low cost but effective biosorbent for heavy metals remediation.


2014 ◽  
Vol 955-959 ◽  
pp. 2453-2457
Author(s):  
Hui Yang ◽  
Meng Zhao ◽  
Ji Gang Yang ◽  
Xin Chai ◽  
Yue Xu

This document studies test methods on modification of activated carbon by potassium permanganate to adsorb Cu2+. Ensure all factors’ effects on Cu2+ removal. Use potassium permanganate solution to modify activated carbon, investigate main factors’ effects on Cu2+ removal and analyze mechanism by changing potassium permanganate solution concentration, adsorption time, activated carbon’s additive amount and temperature. The results show that modification of activated carbon by 0.03mol/L potassium permanganate solution (0.03K-GAC) can adsorb Cu2+ best. 0.03K-GAC’s removal rate on Cu2+ is 98% when the initial concentration of Cu2+ is 50mg/L, the additive amount of 0.03K-GAC is 2.0g, the pH value is 5.5, the temperature is 25°C and the adsorption time is 4h. Modification of activated carbon by potassium permanganate has good adsorbability on Cu2+. Potassium permanganate solution concentration, adsorption time and additive amount can influence the adsorption of Cu2+ by activated carbon. However, temperature’s influence on the effect of adsorption is non-significant.


2021 ◽  
Vol 13 (8) ◽  
pp. 1512-1520
Author(s):  
MiaoSen Zhang ◽  
SiYang Wang ◽  
Zheng Hu ◽  
RunZe Zhang ◽  
XiaoLi Wang

China is a big coal producing country, there are a lot of coal gangue piled up. The zeolite X was synthesized by alkali melting and hydrothermal method based on the coal gangue from Chifeng city, Inner Mongolia. The obtained zeolite X sample is characterized by X-ray diffraction, SEM, EDS spectrum and IR which showed the X zeolite is an octahedral structure with complete crystal shape and uniform grain size. The results of BET showed the specific surface area of zeolite X is 354.8 m2/g and the minimum pore size is 3.8 nm which indicated that the zeolite X belongs to mesoporous materials. The adsorption conditions of the zeolite X adsorbent on copper ions were optimized. A solution containing Cu2+ ions with an initial concentration of 300 mg/L was added to the zeolite X with a dosage of 0.1 g and the initial pH value of the solution was adjusted to 6. Then the solution was oscillated for 120 min at 225 r/min. The maximum adsorption capacity and removal rate were 148.6 mg/g and 99.1%, respectively. The adsorption mechanism was discussed by adsorption kinetics and thermodynamics. The quasi-second order kinetic equation can be well used to describe the adsorption kinetics of zeolite X to Cu2+ (R2 = 0.9994) and Langmuir can well describe the adsorption behavior of zeolite X to Cu2+ (R2 = 0.9995) which showed the adsorption is a monolayer of chemical adsorption. The adsorption capacity of zeolite X to Cu2+ is about 4.0 times that of coal gangue, indicating that the zeolite X has good adsorption capacity.


2013 ◽  
Vol 68 (7) ◽  
pp. 1614-1621 ◽  
Author(s):  
Jimin Shen ◽  
Jiayi Zhu ◽  
Yanli Kong ◽  
Tianwen Li ◽  
Zhonglin Chen

The removal of p-chloronitrobenzene (pCNB) was investigated by a heterogeneous Fenton-like system using a laboratory synthesized goethite (FeOOH) as catalyst. The influencing factors and the degradation pathway of pCNB were also evaluated. With a stronger catalytic activity than Fe2+ catalyst, the synthesized FeOOH catalyst can significantly promote the decomposition of H2O2, and the decomposition product hydroxyl radicals (·OH) can oxidize pCNB in the water effectively. The FeOOH catalyst can also adsorb a certain amount of pCNB, and the adsorption effect is related to the amount of FeOOH and the initial pH value of solution. The results of liquid chromatography–mass spectrometry (LC-MS) and gas chromatography–mass spectrometry (GC-MS) showed that the main intermediate products were phenolic compounds and carbonyl compounds. About 60% of pCNB was mineralized during the catalytic oxidation, and chlorine and nitro groups on benzene ring were converted into Cl− and NO3− after being attacked.


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