scholarly journals Settleability and Dewaterability of Sewage Sludge with Modified Diatomite

Author(s):  
Ling-Yu Wang ◽  
Xue Li ◽  
Kun Luo ◽  
Yu-Hao Song ◽  
Ren-Guo Liu

Abstract In this study, cationic polyacrylamide (CPAM) modified diatomite and cetyl trimethyl ammonium bromide (CTAB) modified diatomite were synthesized and used as conditioner in sewage sludge dewatering. The effects of these two types of modified diatomite on the dewaterability and settling performance of activated sludge were studied. The mechanism of the two types of modified diatomite in the activated sludge system was elucidated. The efficiency of CPAM-modified diatomite was better than that of CTAB-modified diatomite in improving the settleability and dewaterability performance of sludge. The results indicated that specific resistance to filtration (SRF) was decreased from 8.52×1012m/Kg to 0.92×1012 m/Kg, and the water content in the remaining sludge cake after pumping filtration was decreased from 92.2% to 68.1%. by adding 0.4% of CPAM-modified diatomite and pH=3.5, which result in optimal sludge settling of activated sludge. Further studies showed that the polymer/surfactant adsorbed in diatomite increased sludge dewaterability and improved the sedimentation rate as a result of stripping extracellular polymer substances (EPS) and damaging the internal structure of sludge conduce bound water releasing. According to scanning electron microscope(SEM) images, two types of modified diatomite powder not only kept the porous, but also shown more complete and uniform structure in comparison to nature diatomite.

Author(s):  
Shailesh R. Sheth ◽  
Jayesh R. Bellare

Specimen support and astigmatism correction in Electron Microscopy are at least two areas in which lacey polymer films find extensive applications. Although their preparation has been studied for a very long time, present techniques still suffer from incomplete release of the film from its substrate and presence of a large number of pseudo holes in the film. Our method ensures complete removal of the entire lacey film from the substrate and fewer pseudo holes by pre-treating the substrate with Gum Arabic, which acts as a film release agent.The method is based on the classical condensation technique for preparing lacey films which is essentially deposition of minute water or ice droplets on the substrate and laying the polymer film over it, so that micro holes are formed corresponding to the droplets. A microscope glass slide (the substrate) is immersed in 2.0% (w/v) aq. CTAB (cetyl trimethyl ammonium bromide)-0.22% (w/v) aq.


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1617
Author(s):  
Silviu-Adrian Predoi ◽  
Carmen Steluta Ciobanu ◽  
Mikael Motelica-Heino ◽  
Mariana Carmen Chifiriuc ◽  
Monica Luminita Badea ◽  
...  

In the present study, a new low-cost bioceramic nanocomposite based on porous hydroxyapatite (HAp) and cetyl trimethyl ammonium bromide (CTAB) as surfactant was successfully obtained by a simple chemical co-precipitation. The composition and structure of the HAp-CTAB were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) spectrometer, and N2 adsorption/desorption analysis. The capacity of HAp-CTAB nanocomposites to remove the lead ions from aqueous solutions was studied by adsorption batch experiments and proved by Langmuir and Freundlich models. The Pb2+ removal efficiency of HAp-CTAB biocomposite was also confirmed by non-destructive ultrasound studies. The cytotoxicity assays showed that the HAp-CTAB nanocomposites did not induce any significant morphological changes of HeLa cells after 24 h of incubation or other toxic effects. Taken together, our results suggests that the obtained porous HAp-CTAB powder could be used for the decontamination of water polluted with heavy metals, such as Pb2+.


2014 ◽  
Vol 665 ◽  
pp. 404-407 ◽  
Author(s):  
Wan Yu ◽  
Pei Sheng Li

Moisture distribution in sewage sludge was considered as the essential of thermal drying. Some methods were given in literatures to test the moisture distribution, but there was no standard method to determine the critical water content between different kinds of water. The municipal sewage sludge was dried by hot air in this work. Based on the drying curve, the derivative of drying rate with respect to dry basis moisture content was brought out to analyze the moisture distribution in sewage sludge. Results show that this method can easily determine the free water, interstitial water, surface water and bound water with a high accuracy. The present work can provide new insight to determine the moisture distribution in sewage sludge, which was still lacking in the literatures.


2011 ◽  
Vol 71-78 ◽  
pp. 122-125 ◽  
Author(s):  
Ling Li Song ◽  
Ren Yuan Zhang ◽  
Ling Bo Mao ◽  
Wen Jie Zhu ◽  
Miao Yan Zheng

The influences of dispersant type, supersonic time and concentration on the dispersion property of the nano-aluminium powders in glycol water were systematically studied by using Sodium dodecyl sulfate (SDS),cetyl trimethyl ammonium bromide (CTAB) and sodium hexa metah posphate(SHMP)as dispersants. During the first stage of the experiments, influences of dispersant type and ultrasonic time with these dispersants were evaluated. The next stage of the study was focused on SHMP concentration. The influence of SHMP concentration was assessed. The results show that with the increasing of ultrasonic time, the dispersion property of nano-aluminum powders first increases and then decreases, and SHMP is the best one. The excellent dispersing condition on the dispersion property of nano-aluminium is: 5g/L SHMP and 50 min ultrasonic vibration.


1986 ◽  
Vol 64 (4) ◽  
pp. 299-304 ◽  
Author(s):  
Shoji Hashimoto ◽  
Koichi Nishimura ◽  
Waichiro Kawakami ◽  
Hiroshi Watanabe

Author(s):  
Saurabh Singh ◽  
Bimlesh Kumar ◽  
Narendra Kumar Pandey ◽  
Barinder Kaur ◽  
Arun Kumar ◽  
...  

Objective: The present study highlights the development of a method to synthesize copper nanoparticles (CuNPs).Methods: CuNPs were developed using 0.01 M copper penta sulfate and 0.11 M of ascorbic acid (AA) and 0.03 M of cetyl trimethyl ammonium bromide solution. The synthesized CuNPs were differentiated through filtration and washed by water (deionized). CuNPs were kept in dialysis bag 70 KD in a 250 mL glass beaker along with distilled water. The assembly was kept on a magnetic stirrer for 24 h at 500 rpm. Then, the dialysis bag containing CuNPs solution was filtered by a filter assembly with 0.2 μm nylon filter. The filtered CuNPs were spray dried with the help of spray drier.Results: The prepared CuNPs were found to be 440 nm with zeta potential of −10 mV and polydispersity index 0.314.Conclusion: The investigation deciphers the promising and material technique to synthesis of CuNPs by methods for synthetic reduction utilizing strategy using AA (0.2 M) and sodium hydroxide (1 M), and Syloid 244FP.


2015 ◽  
Vol 7 (3) ◽  
pp. 372-381
Author(s):  
Comfort O. AFOLAYAN ◽  
Michael Olugemi AWODIRAN

The genetic differentiation of Archachatina marginata populations from three different zones of Nigeria was studied with a view to delimiting them into sub-species. One hundred and nineteen (119) snail specimens were collected, comprising of forty (40) specimens from Yenagoa (Mangrove forest) and from Kabba (Guinea Savanna) and thirty nine (39) specimens were from Ile-Ife (Rainforest). Eight parameters of the shell specimens of A. marginata which included height of shell, width of shell, aperture height, aperture width, spire length, spire width, penultimate whorl length and first whorl length were subjected to Principal Component Analysis (PCA) and Canonical Variates Analysis (CVA) to delimit the populations into sub-species. DNA of the various populations was extracted from the foot muscle using CTAB (Cetyl Trimethyl Ammonium Bromide) method, which was subjected to RAPD analysis. The RAPD studies employed five (5) oligonucleotide primers (OPB – 17, OPH – 12, OPH – 17, OPI – 06 and OPU – 14) to amplify DNA from 27 samples of A. marginata selected. All five primers produced different band patterns, and the number of fragments amplified per primer varied. Among them, OPB- 17 gave DNA profiles with more numerous bands than the others primers. Both PCA and CVA produced overlapped clusters of A. marginata specimens from the three vegetation zones. The height of shell was observed to be the most variable feature and preferably the most suitable parameter for population grouping. Analysis of the proportions of polymorphic loci and band sharing based on similarity indices for A. marginata samples indicated a relatively high level of genetic variation in the populations from the three areas.


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