Application of economical models for dye removal from aqueous solutions: cash flow, cost–benefit, and alternative selection methods

2013 ◽  
Vol 16 (2) ◽  
pp. 423-429 ◽  
Author(s):  
Utkan Ozdemir ◽  
Ismail Ozbay ◽  
Bilge Ozbay ◽  
Sevil Veli
2020 ◽  
Vol 9 (1) ◽  
pp. 770-782
Author(s):  
Tianpeng Li ◽  
Jing Fan ◽  
Tingting Sun

AbstractA novel porous ceramsite was made of municipal sludge, coal fly ash, and river sediment by sintering process, and the performance of batch and fixed-bed column systems containing this material in the removal of acid red G (ARG) dye from aqueous solutions was assessed in this study. The results of orthogonal test showed that sintering temperature was the most important determinant in the preparation of porous ceramsite, and it possesses developed pore structure and high specific surface area. Batch experiment results indicated that the adsorption process of ARG dye toward porous ceramsite was a spontaneous exothermic reaction, which could be better described with Freundlich–Langmuir isotherm model (R2 > 0.992) and basically followed the pseudo-first-order kinetic equation (R2 > 0.993). Column experiment results showed that when the porous ceramsite was used as packing material, its adsorption capacity was roughly improved by 3.5 times compared with that in batch system, and the breakthrough behavior was simulated well with Yoon–Nelson model, with R2 > 0.954. This study suggested that the novelty man-made porous ceramsite obtained from solid wastes might be processed as a certain cost-effective treatment material fit for the dye removal in aqueous solutions.


Heliyon ◽  
2021 ◽  
pp. e07191
Author(s):  
Fateme Barjasteh-Askari ◽  
Mojtaba Davoudi ◽  
Maryam Dolatabadi ◽  
Saeid Ahmadzadeh

Author(s):  
Karine Cappuccio de Castro ◽  
Vitória Fernandes Cintra Leme ◽  
Flavia Helena Moreti Souza ◽  
Giovanna Oliveira Barros Costa ◽  
Gabriela Espirito Santos ◽  
...  

2018 ◽  
Vol 54 (4) ◽  
pp. 1615-1642
Author(s):  
Sean J. Griffith ◽  
Natalia Reisel

We investigate the Dead Hand Proxy Put, a contractual innovation in corporate debt agreements that may impact hedge fund activism. We find the provision principally in loans, not bonds, and provide evidence linking the adoption of the provision to hedge fund activism. Furthermore, controlling for endogeneity, we find that the provision significantly reduces the cost of loans. Bondholder wealth also increases. Moreover, cross-sectional analysis of share returns reveals that the provision is positively associated with repeat banking relationships and negatively associated with free cash flow problems, suggesting a cost-benefit tradeoff.


RSC Advances ◽  
2014 ◽  
Vol 4 (52) ◽  
pp. 27354-27362 ◽  
Author(s):  
Simona Gabriela Muntean ◽  
Maria Elena Rădulescu-Grad ◽  
Paula Sfârloagă

The efficiency of styrene-divinylbenzene functionalized with trimethylamonium groups as sorbent for the direct dye removal from aqueous solutions was investigated.


2015 ◽  
Vol 18 (1) ◽  
pp. 38-46 ◽  

<div> <p>This study was conducted to investigate the effect of praestol, as a coagulant-aid, to improve coagulation-flocculation process in the removal of disperse red 60 from aqueous solutions. The effect of various parameters including coagulants dose (10-1000 mg l<sup>-1</sup>), praestol dose (0-1000 mg l<sup>-1</sup>), solution pH (3-11), initial dye concentration (100-500 mg l<sup>-1</sup>), flocculation speed (30-60 rpm), flocculation time (15-30 min), settling time (5-60 min) and ionic strength (0-6 mg l<sup>-1</sup>) was evaluated on the dye removal. The dye removal efficiency was substantially increased by using praestol in the concentration of 80 mg l<sup>-1 </sup>and 400 mg l<sup>-1 </sup>for coagulation with alum and polyaluminum chloride (PACl), respectively. The maximum dye removal by alum coupled with praestol (Al-P) and PACl coupled with praestol (PA-P) was found to be 97.8% and 98.7%, respectively that were occurred at pH 7. The results showed that the application of PA-P or Al-P can be effectively used to remove disperse red 60 (DR 60) in aqueous solutions.</p> </div> <p>&nbsp;</p>


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