scholarly journals Removal of Fluorides from Aqueous Solutions Using Exhausted Coffee Grounds and Iron Sludge

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1512
Author(s):  
Irma Siaurusevičiūtė ◽  
Ramunė Albrektienė

Many countries are confronted with a striking problem of morbidity of fluorosis that appears because of an increased concentration of fluorides in drinking water. The objective of this study is to explore opportunities for removal of fluoride from aqueous solutions using cheap and easily accessible adsorbents, such as exhaustive coffee grounds and iron sludge and to establish the efficiency of fluoride removal. Twelve doses (1, 2, 3, 4, 5, 6, 10, 20, 30, 40, 50 and 60 g/L) of adsorbents were used and five durations of the sorption process (30, 60, 90, 120 and 150 min). The results showed that the most optimum dose of iron sludge for 3 mg/L of fluoride removal was 30 g/L and the contact time was 30 min, the efficiency of fluoride removal achieved 62.92%; the most optimum dose of exhausted coffee grounds was 60 g/L with the most optimum contact time of 60 min; at a dose of 50 g/L with contact time of 90 min, the efficiency of fluoride removal achieved 56.67%. Findings demonstrate that adsorbents have potential applicability in fluoride removal up to the permissible norms.

2012 ◽  
Vol 573-574 ◽  
pp. 150-154
Author(s):  
Yun Bo Zang ◽  
Nai Ying Wu

In this study, removal of copper ions from aqueous solutions by synthetic Mg-Al-HTlc was investigated as a function of contact time, EDTA and addition sequences at room temperature. It is found that HTlc could reduced copper ions concentration effectively. The kinetics closely fit pseudo-second order kinetics with necessary time 9 h to reach equilibrium. The sorption process followed langmuir model. The maximum sorption capacity calculated was found to be 39.4 mg/g. The presence of EDTA and addition sequences could affect sorption of Cu(II) onto HTlc.


2021 ◽  
Author(s):  
Samina Zaman ◽  
Md. Nayeem Mehrab ◽  
Md. Shahnul Islam ◽  
Gopal Chandra Ghosh ◽  
Tapos Kumar Chakraborty

Abstract This study investigates the potential applicability of hen feather (HF) to remove methyl red (MR) dye from aqueous solution with the variation of experimental conditions: contact time (1–180 min), pH (4–8), initial dye concentration (5–50 mg/L) and adsorbent dose (3–25 g/L). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) evaluate the surface morphology and chemistry of HF, respectively. The maximum removal of MR by HF was 92% when the optimum conditions were initial MR dye concentration 05 mg/L, pH 4.0, adsorbent dose 07.0 g/L and 90.0 min equilibrium contact time. Langmuir isotherm (R2 = 0.98) was more suited than Freundlich isotherm (R2 = 0.96) for experimental data, and the highest monolayer adsorption capacity was 6.02 mg/g. The kinetics adsorption data fitted well to pseudo-second-order model (R2 = 0.999) and more than one process were involved during the adsorption mechanism but film diffusion was the potential rate-controlling step. The findings of the study show that HF is a very effective and low-cost adsorbent for removing MR dye from aqueous solutions.


2013 ◽  
Vol 726-731 ◽  
pp. 695-699
Author(s):  
Li Hong ◽  
Si Xiang Wang ◽  
Yong Liu ◽  
Yue Chun Zhang

Humic acid adsorbent modified with metal ions was prepared by gel polymerization and named gel composite of metal ion and humic acid, which abbreviated GCMH to uptake fluoride from drinking water. The samples were measured by X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images. Fluoride adsorption onto the synthesized samples was investigated by batch adsorption method. In previous works, detailed studies were carried out to investigate the effect of contact time, adsorbent dose, initial solution pH, temperatures and co-existing anions. The maximum fluoride removal was obtained at pH7. Presence of HCO3− adversely affected the adsorption of fluoride. The optimum absorption conditions were at the dose of 10g/L, temperature of water of 55°Cand contact time of 6hs.


Author(s):  
C. B. Lopes ◽  
M. Otero ◽  
Z. Lin ◽  
E. Pereira ◽  
C. M. Silva ◽  
...  

Mercury is one of the most toxic heavy metals present in the environment and therefore is extremely important develop new, simple and reliable techniques for its removal from aqueous solutions. A recent line of research within this context is the application of microporous materials. The use of these materials for removing heavy metals from solutions may become a potential clean-up technology in the field of wastewater treatment. In this work it is reported the application of microporous titanosilicate ETS-4 as ion exchanger to remove Hg2+ from aqueous solution. Under batch conditions, we studied the effect of contact time, titanosilicate mass and initial Hg2+ concentration. Only 5 mg of ETS-4 are required to purify 2 litres of water with 50 μg L−1 of metal. Under the experimental conditions, the initial Hg2+ concentration and ETS-4 mass have strong influence on the sorption process, and it is proved that 24 h are almost always sufficient to attain ion exchange equilibrium. Langmuir and Freundlich isotherms were used to fit equilibrium experimental results. The kinetics of mercury removal was reliably described by a pseudo second-order model. On the whole, ETS-4 shows considerable potential to remove Hg2+ from wastewaters.


2020 ◽  
Vol 5 (2) ◽  
pp. 109-117
Author(s):  
Iohborlang M. Umlong ◽  
Bodhaditya Das ◽  
Rashmi Rekha Devi

Presence of fluoride in drinking water above the prescribed limit may lead to a severe health complication. We present in this paper the fluoride removal capacity of cement impregnated MgO (MgO-cement) from drinking water. MgO-cement was prepared by adding magnesium oxide (MgO) into the cement slurry solution in the ratio of 1:10. Batch experiments were performed as a function of adsorbent dose, contact time, effect of pH and effect of co-ions. The percentage removal decreases with increasing initial fluoride concentration. Co-ions effect revealed that hydroxide ion was found to interfere more with fluoride removal followed by bicarbonate and least effect with sulphate. Reaction mechanism follows Freundlich isotherms. From the kinetic study we observed that uptake of fluoride ion is fast in the first sixty minutes and equilibrium time found to be independent of the initial fluoride concentration. Adsorption kinetics followed the pseudo second order model showing that the sorption of fluoride is a complex process. Surface as well as intraparticle diffusion contribute in the sorption process. No leaching of magnesium in the treated water was detected.


Author(s):  
Kefelegn Bayu ◽  
Abraham Geremew ◽  
Wegene Deriba ◽  
Yohannes Mulugeta ◽  
Samuel Wagari ◽  
...  

Abstract Fluoride concentration in drinking water higher than recommended value imposes different health problems and there are advanced and chemical based defluoridation techniques even if they are not feasible for developing countries and have limitations. Due to this, defluoridation by using locally available plants is one of the most efficient and sustainable options. Therefore, the current study was intended to investigate fluoride removal efficiency of Tulsi (Ocimum Sanctum) from water that can be an alternative means to reduce the problem related to its high concentration. A laboratory based experimental study was implemented by using potentiometric determination in Haramaya University. The leaves of Tulsi were collected, washed with tap water, rinsed with distilled water, and then were dried at room temperature, crushed and sieved through 500-μm stain-less steel sieve. The experiments were conducted on artificially fluoridated water by anhydrous fluoride and natural water samples collected from deep well water sources from Adama and Harar town. Data was analyzed using Design of Expert (DOE) and Microsoft excel. Twenty-nine runs for aqueous solution were conducted at different factor combinations and the optimum combinations were applied for natural water samples. The study depicts that plant has an efficiency of removing 68.4% of fluoride from water. The best factor combinations to achieve this efficiency was 0.2 g/100 ml, 22.6 min, 5.7 and 6.6 mg/l, adsorbent dose, contact time, pH and initial concentration respectively. pH and initial concentration have a negative effect and adsorbent dose and contact time have a positive effect on removing fluoride from water. Hence, people living in fluorosis endemic areas can use the processed plant as a de-fluoridating agent to minimize adverse health effects. HIGHLIGHT This research articles paves way to further study to remove contaminants from water, wastewater, which can pose a substantial effect on public health. The study conducted to investigate removal mechanism of fluoride from drinking water with low cost locally available plant and the software technologies were applied to find the optimum conditions at which the adsorbent works best.


2020 ◽  
Vol 27 (1) ◽  
pp. 67-82
Author(s):  
Ramunė Albrektienė ◽  
Dainius Paliulis

AbstractLead is a heavy metal with strong toxic properties. This chemical element is found in wastewater and sometimes in drinking water. The article deals with the removal of lead(II) ions from polluted water using a sorption process to determine the most effective sorbent for the removal of lead(II) ions. Three sorbents were used in the research: clay, sapropel, and iron sludge. All three sorbents investigated reduce the concentration of lead(II) ions in water: clay efficiency was of 65.7–90 %, sapropel of 94.3–100 %, and iron sludge of 84.3–97 %, depending on sorbent type and contact duration. The research has shown that the most effective way to remove lead(II) ions from the test water is sapropel. Using different amounts of sapropel (1, 2, 3, 4, 5, 6 g/dm3 and 0.1, 0.2, 0.4, 0.5, 0.6, 0.8 g/dm3) and different duration of contact (30, 60, 90, 120 and 150 minutes), the concentration of lead(II) ions in the test water after purification did not exceed the permissible values for drinking water (10 μg/dm3), so that the lowest sapropel content of 0.1 g/dm3 can be used for sorption. Lead(II) ions are most effectively removed when contact time is 30 min.


2014 ◽  
Vol 539 ◽  
pp. 823-826
Author(s):  
Hong Hai Sun

In this study, the palm leaves powder was used as adsorbent for the removal of rhodamine B (RhB) from aqueous solutions. The effects of initial RhB concentrations, adsorbent dosage, initial solution pH and contact time on the amount of color removal was investigated. Batch kinetics and isotherm studies were conducted to evaluate the adsorption behavior of the palm leaves powder. TheLangmuir and Freundlich isotherm model were used to describe the equilibria data. Further, the kinetics involved in the sorption process was evaluated at different initial RhB concentrations.


2006 ◽  
Vol 4 (1) ◽  
pp. 139-147 ◽  
Author(s):  
M. E. Kaseva

This paper presents findings of a study on optimization and application of the regenerated bone char media for the defluoridation of drinking water in Tanzania where more than 30% of all water sources have fluoride concentrations above the 1.50 mg/l which is recommended by the World Heath Organization (WHO). In this study, regeneration temperature, regeneration duration, contact time, regenerated bone char dosage and particle size were investigated. Results indicate that the highest fluoride removal and adsorption capacity were 70.64% and 0.75 mg-F/g-bc, respectively, for a sample with bone char material that was regenerated at 500°C. In this study the optimum burning duration was found to be 120 min, which resulted in residual fluoride that varied from a maximum value of 17.43 mg/l for a 2 min contact time to a minimum value of 8.53 mg/l for a contact time of 180 min. This study further indicated that the smallest size of regenerated bone char media (0.5–1.0 mm diameter) had the highest defluoridation capacity, with residual fluoride which varied from 17.82 mg/l at 2 min contact time to 11.26 mg/l at 120 min contact time. In terms of dosage of the regenerated bone char media it was established that the optimum dosage was 25 g of bone char media with a grain size of 0.50–1.0 mm. This had a fluoride removal capacity of 0.55 mg-F/g-BC. Column filter experiments indicated that regenerated bone media is capable of removing fluoride from dinking water to meet both WHO and Tanzania recommended values.


2012 ◽  
Vol 9 (4) ◽  
pp. 1843-1853 ◽  
Author(s):  
Amir Hossein Mahvi ◽  
Behzad Heibati ◽  
Alireza Mesdaghinia ◽  
Ahmad Reza Yari

Drinking water provides many vital elements for the human body, but the presence of some dissolved elements more than permissible concentration can endanger human health. Among the dissolved elements in drinking water, fluoride is noticeable, because both the very low or very high concentrations have adverse health impacts such as dental caries. Therefore, fluoride concentration should be kept in acceptable levels. In this study Pumice was used for fluoride removal. It was found that Fluoride sorption kinetic was fitted by pseudo-second-order model. The maximum sorption capacity of Pumice was found to be 13.51 mg/g at laboratory temperature (24°C). Maximum sorption study occurred at pH= 3. Results of Isotherm showed the fluoride sorption has been well fitted with Freundlich isotherm model. This study has demonstrated that Pumice can be used as effective adsorbents for fluoride removal from aqueous solutions. The adsorbent prepared in this study was cheap and efficient in removal of fluoride than other adsorbents.


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