scholarly journals Efficacy of Chitosan as a Coagulant Aid to Alum Precipitation of Congo Red In Wastewater

2021 ◽  
pp. 37-44
Author(s):  
Adelagun Ruth Olubukola Ajoke ◽  
Magomya Asabe Mercy ◽  
Kamba Emmanuel Alhassan

The use of chitosan prepared from prawn shells as coagulant aid for congo red (CR) dye removal from wastewater was investigated in this study. Characterisation of the prepared chitosan samples showed characteristics similar to commercially available ones. The coagulation – flocculation experiment was carried out using the jar test procedure. Both chitosan and alum were used separately for the dye precipitation and then combined together. The usage of alum alone showed no precipitating effect on the CR dye molecule, while chitosan was able to considerably reduce the concentration of the dye in solution. When chitosan was used as a coagulant aid in the alum precipitation, the amount (%) of dye removed increased greatly. Optimization of the process via study of effect of pH and flocculation time at optimum alum – chitosan combination indicated that pH 4-5 and settling time of 40 min were suitable conditions for maximum decolourisation of CR dye wastewater with about 98% efficiency. Moreover, study of settling characteristics of the sludge produced from the alum-chitosan synergy was better than that produced from either of them alone. Also, occurrence of redispersion and restabilization of the precipitate was not encountered.

2018 ◽  
Vol 24 (1) ◽  
pp. 69-76 ◽  
Author(s):  
M.S. Zafar ◽  
S.W. Ahmad ◽  
M. Zia-Ul-Haq ◽  
A. Mubeen ◽  
W.A. Khan

Due to inefficient dyeing procedures in a typical dye industry, a large quantity of dye spills out into the wastewater, polluting it and causing serious harm to the environment. Consequently, special attention was focused on the use of a novel combination of a coagulant and a flocculant. As potato starch has already proved its strength as a bioflocculant, a combination of potato starch with iron(III) chloride as a coagulant was tested in order to achieve favorable results of dye reduction in simulated wastewater. The effect of various parameters on dye removal was investigated, like dosage of flocculant, temperature of treatment and flocculation time. Batch experimentation mode was adopted for the flocculation process, using a jar test apparatus. A mixed level parametric design (L16) was employed for experimentation. The orthogonal tests revealed that the best operating parameters were: 2% of potato starch, 60?C and 20 min of flocculation time. Furthermore, the significant factor test was performed using Minitab-17 from where the dosage of potato starch was proven to be the most significant factor. The study successfully raised dye removal efficiency up to 85% using a novel coagulant-flocculant combination. Finally, the results were compared with existing literature.


2008 ◽  
Vol 43 (2-3) ◽  
pp. 231-238 ◽  
Author(s):  
Nurudeen A. Oladoja ◽  
Yekini D. Aliu

Abstract The use of plantain peelings ash extract (PPAE) as a coagulant aid in a low pH water was evaluated in the present studies. Plantain peelings were collected, washed, dried, and ashed in a furnace. The ash was extracted using deionized water, and the chemical composition was examined using an atomic absorption spectrophotometer. Synthetic turbid water of varying turbidities (50, 100, 300 NTU) and varying pHs (2, 3, 4) were prepared by clay dispersion in deionized water. The optimum alum dosages for the coagulation of colloidal particles in different turbid waters of varying pHs were determined by method of continuous variation using the jar test procedure. The residual turbidities of the treated waters were determined, and the alum doses that gave the minimum residual turbidities were taken as the optimum dosage for the removal of colloidal particles. The use of PPAE as a coagulant aid with alum showed an improvement in the value of residual turbidities of the treated waters. Results obtained from the different studies showed that treated waters of lower residual turbidities were obtained from synthetic waters of higher initial turbidities and pHs. The pH of the treated water decreased with an increase in alum dosage, whereas an increase in the pH value was observed with the addition of PPAE as a coagulant aid. High correlation coefficient values (r2) were obtained when the changes in pH (i.e., ΔpH = pHf –pHi) of the treated waters were correlated with alum and PPAE additions, and mathematical relationships were derived from the linear graph. Studies on the effect of flocculation time on residual turbidity showed that an optimum flocculation time of 30 minutes was attained, when alum was used alone, before redistribution and redispersion of the flocs was noticed. This phenomenon did not occur when PPAE was used as a coagulant aid.


1996 ◽  
Vol 33 (9) ◽  
pp. 117-125 ◽  
Author(s):  
Emmanuelle Aiguier ◽  
Ghassan Chebbo ◽  
Jean-Luc Bertrand-Krajewski ◽  
Peter Hedges ◽  
Naomi Tyack

Recently, research has shown that a settling process is an efficient treatment for the removal of suspended solids from storm sewage. In order to design settling tanks, there is a need to determine the settling velocity characteristics of these solids. Devices and test methods for measuring settling velocities of solids in storm sewage have been developed by researchers. A literature review has revealed that the settling velocity profiles obtained with some methods (Chebbo, 1992), (Michelbach and Wohrle, 1993) and (Tyack et al., 1993) are very different. In order to explain why the results are different and to quantify the influence of the experimental procedure on the settling velocity grading curves, we have compared the selected methods when tested with the same sample and we have studied the effects of the conservation of the sample before the test, of the concentration of solids in the device and of the nature of the water on the settling velocity profiles. The results of the comparative tests indicate that the settling velocities are significantly lower with both the Cergrene and Aston methods than with the UFT test procedure. Moreover, the study has shown that the settling characteristics of solids change with time, that the use of sewage liquor rather than demineralised water or drinking water can change the results of the measurement and that the higher the concentration of solids, the greater the velocity of settled particles.


2021 ◽  
Vol 765 (1) ◽  
pp. 012089
Author(s):  
R Taufik ◽  
M Mohamad ◽  
R Wannahari ◽  
N F Shoparwe ◽  
WHW Osman ◽  
...  

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 384
Author(s):  
Ahmed Labena ◽  
Ahmed E. Abdelhamid ◽  
Abeer S. Amin ◽  
Shimaa Husien ◽  
Liqaa Hamid ◽  
...  

Biosorption is a bioremediation approach for the removal of harmful dyes from industrial effluents using biological materials. This study investigated Methylene blue (M. blue) and Congo red (C. red) biosorption from model aqueous solutions by two marine macro-algae, Ulva fasciata and Sargassum dentifolium, incorporated within acrylic fiber waste to form composite membranes, Acrylic fiber-U. fasciata (AF-U) and Acrylic fiber-S. dentifolium (AF-S), respectively. The adsorption process was designed to more easily achieve the 3R process, i.e., removal, recovery, and reuse. The process of optimization was implemented through one factor at a time (OFAT) experiments, followed by a factorial design experiment to achieve the highest dye removal efficiency. Furthermore, isotherm and kinetics studies were undertaken to determine the reaction nature. FT-IR and SEM analyses were performed to investigate the properties of the membrane. The AF-U membrane showed a significant dye removal efficiency, of 88.9% for 100 ppm M. blue conc. and 79.6% for 50 ppm C. red conc. after 240 min sorption time. AF-S recorded a sorption capacity of 82.1% for 100 ppm M. blue conc. after 30 min sorption time and 85% for 100 ppm C. red conc. after 240 min contact time. The membranes were successfully applied in the 3Rs process, in which it was found that the membranes could be used for five cycles of the removal process with stable efficiency.


2021 ◽  
pp. 111492
Author(s):  
Dang Le Tri Nguyen ◽  
Quach An Binh ◽  
Xuan Cuong Nguyen ◽  
Thi Thanh Huyen Nguyen ◽  
Quang Nha Vo ◽  
...  

2001 ◽  
Vol 44 (10) ◽  
pp. 231-236 ◽  
Author(s):  
J. Gregory ◽  
V. Dupont

Hydrolyzing coagulants are extensively used in water and wastewater treatment, often under conditions where hydroxide precipitation is important, giving “sweep flocculation”. Pre-hydrolyzed coagulants, such as polyaluminium chloride (PACl) are also widely used and have several advantages over traditional additives, such as aluminium sulfate. Their action is usually discussed in terms of cationic species and charge neutralization. However, precipitation may also be important and this aspect has not been considered in detail. The present work has compared the action of alum and three commercial PACl products on model clay suspensions. The conventional jar test procedure has been used, along with measurements of settled floc volume and dynamic monitoring of floc formation and break-up by an optical technique. The latter method gives very useful information on the nature of the flocs produced and their response to different shear conditions. It is clear from the results that the PACl products form larger and stronger flocs than alum. With all coagulants floc breakage appears to be essentially irreversible. Sediment volumes are slightly lower for flocs produced by PACl than by alum, but the value is proportional to the dosage in all cases.


2018 ◽  
Author(s):  
Bakri Rio Rahayu ◽  
Tarmizi Taher ◽  
Poedji Loekitowati Hariani ◽  
Aldes Lesbani

Author(s):  
Amaia Menendez ◽  
Jose Ignacio Lombraña ◽  
Ana de Luis

AbstractSynthetic dyes are extensively used in textile dyeing, paper printing, colour photography, pharmaceuticals, food, cosmetics and other industries. In spite of their diversity there are a certain number of properties common to many dye compounds, such as aromatic constitution, chromophore groups and others. Similarly to other dyes and due to the formation of colour intermediates, in the case of Rhodamine 6G colour capacity is maintained in the initial steps of dye degradation. For this reason in the degradation of a dye it is necessary to distinguish between two processes that take place simultaneously: dye removal and decolourization. This study was conducted by using a water solution of 50 mg/L of Rhodamine 6G (Rh-6G), as a model of a dye wastewater, in the hydrogen peroxide/UV system. The kinetic model proposed in this paper for the removing of Rh- 6G is a sequential first-order reaction. This model describes acceptably the changes in two kinds of compound for a wide interval of H


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