Removal of fluoride and natural organic matter from natural tropical brackish waters by nanofiltration/reverse osmosis with varying water chemistry

Owusu-Agyeman, Isaac; Reinwald, Michael; Jeihanipour, Azam; Schäfer, A.I.

doi:10.1016/j.chemosphere.2018.10.135

Cited by 66 publications

(16 citation statements)

References 52 publications

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“…At high pH, the surface charge of the TFC NF/RO membrane became more negatively charged, and most NOM may become more negative, which would result in high TOC removal due to enhanced charge exclusion [24,71]. Surprisingly, the results show the opposite trend.…”

Section: Impact Of Groundwater Ph On Organic Matter Removalmentioning

confidence: 93%

“…This could be explained well by comparing the LC-OCD results between feed and permeate samples. While the water samples from Tanzania were not sent for LC-OCD analysis and no instrument was available on site, samples from different experiments that were sent for LC-OCD analysis had shown significant regrowth and had to be repeated in a laboratory environment [71]. This is why LC-OCD analysis was performed in a controlled laboratory study at a later date.…”

Section: Impact Of Applied Pressure On Toc Removalmentioning

confidence: 99%

“…Interaction between Ca/Sr and NOM and such gel formation will cause flux decline and potentially fouling during longer-term operation. At high pH, NOM's negative charge may be further enhanced [71], thus probably increasing the interaction between Ca/Sr and NOM.…”

Section: Impact Of Groundwater Ph On Permeate Fluxmentioning

confidence: 99%

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Removal of Naturally Occurring Strontium by Nanofiltration/Reverse Osmosis from Groundwater

2020

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Removal of naturally occurring strontium (Sr) from groundwater is vital as excessive exposure may lead to bone growth problems in children. Nanofiltration/reverse osmosis (NF/RO) is commonly used in groundwater treatment due to the high effectiveness and simple maintenance of these pressure driven membrane processes. In this research, a pilot-scale NF/RO system was used to desalinate a natural groundwater sample containing high Sr concentration (10.3 mg/L) and “old” groundwater organic matter (70.9 mg/L) from Esilalei in northern Tanzania to understand the removal of strontium by NF/RO. The impact of applied pressure (10–15 bar) and groundwater pH (3–12) on the membrane performance including permeate flux, strontium and total organic carbon (TOC) flux and removal was investigated. Increasing applied pressure was found to enhance the flux by increasing the driving force and enhance Sr and TOC removal by dilution effect (water flux higher than Sr passage). The alkaline pH caused severe flux decline likely due to membrane fouling and scaling, while it slightly enhanced Sr removal of RO membranes, but weakened the TOC removal. In contrast, acidic and neutral pH of groundwater enhanced TOC removal. These findings suggest that appropriately high applied pressure and acidic pH condition of groundwater are recommended to apply to the NF/RO membrane system in groundwater desalination to achieve better membrane performance.

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Section: Impact Of Groundwater Ph On Organic Matter Removalmentioning

confidence: 93%

Section: Impact Of Applied Pressure On Toc Removalmentioning

confidence: 99%

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Removal of Naturally Occurring Strontium by Nanofiltration/Reverse Osmosis from Groundwater

2020

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“…They have focused their attention on the multiple aspects that can affect the removal of fluoride, such as operating conditions, the presence of organic matter, pH values, and the ionic strength of treated waters, etc. [18,[49][50][51][52][53].…”

Section: Comparison With Literature Datamentioning

confidence: 99%

Fluoride Polluted Groundwaters in Calabria Region (Southern Italy): Natural Source and Remediation

Fuoco

Apollaro

Criscuoli

et al. 2021

Water

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Excessive ingestion of fluoride through the consumption of F−-rich drinking water could cause adverse effects to human health. For this reason, the WHO has fixed 1.5 mg/L as the maximum F- concentration for drinking water. In this work, a detailed geochemical characterization was performed to define the source of natural pollution of two groundwaters (samples Pc and Bg) coming from deep crystalline aquifers located in the Calabria region (southern Italy) and to define and optimize the most appropriate water treatment strategy. The samples were classified as a F− enriched NaHCO3 type of water. In particular, the F− concentrations observed were 30 mg/L and 8.9 mg/L for the Pc and Bg samples, respectively. Based on the acquired geochemical characterization knowledge, the groundwaters were treated by two thin-film composite NF membranes, namely SPR 10113 and SPR 10114 which have so far not been used for water defluoridation. It was found that the SPR 10114 membrane was able to guarantee water permeates with F− contents lower than the threshold value of 1.5 mg/L for both treated waters, whereas the fluoride content remained above the threshold value when the Pc sample was treated using the SPR 10113 membrane. The obtained permeates were characterized by a low ionic load and were not suitable for long-term consumption as drinking water. However, all of the produced waters did not need any further re-mineralizing processes for agricultural irrigation or other purposes.

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“…Due to these impacts on human health and environment, a number of international regulators have issued regulations to control the fluoride levels in water 33,34 . Different processes have been studied to remove excessive fluoride from water namely, biological processes (plants or microorganisms) 35,36 and physicochemical processes such as fluidized bed precipitation 37 , electrocoagulation-flotation 38,39 , ion-exchange 40,41 , electrochemical methods 42 and membrane processes (reverse osmosis 43,44 , electrodialysis 45,46 , Donnan dialysis 47 , nanofiltration 48 , etc.). However, each of these methods presents its drawbacks, such as a long disposal time, the use of dangerous and expensive reagents 49 .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of aluminum-based adsorbent and application in fluoride removal from aqueous solution

2020

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A novel adsorbent was obtained by a facile precipitation method and was used for fluoride removal from aqueous solution. Mineralogical and physicochemical characterization of the adsorbent was carried out by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Energy Dispersive X-Ray attached to Scanning Electron Microscopy (SEM-EDX), BET Specific Surface Area(SSAN2BET) analysis and Fourier-Transform Infrared Spectrometry (FTIR). The effect of various operational parameters such as contact time, initial fluoride concentration, (20-160 mg L-1) adsorbent dose (1-6 g L-1) and initial pH solution (3-11) was evaluated in batch procedures at room temperature (25±2°C). The results of the batch adsorption experiments proved that 24 h of contact time was sufficient for attaining equilibrium. The maximum wastewater defluoridation (84.91%) was obtained for 40 mg L-1 and 3 g L-1 of initial fluoride concentration and adsorbent dose, respectively. It appears that there was no significant effect on the F- removal over a wide range of pH 3-11. Kinetic studies revealed that fluoride adsorption fitted well to pseudo-second-order. The adsorption isotherm of fluoride sorption indicated that the maximum adsorption capacity was noted to be 43.29 mg g-1. Batch adsorption data was better described by Langmuir isotherm confirming monolayer adsorption with homogenous distribution of active sites and without interaction between adsorbed molecules. The obtained results indicated that the ion exchange is probably the main mechanism involved in the F- adsorption by the aluminium-based adsorbent.

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Removal of fluoride and natural organic matter from natural tropical brackish waters by nanofiltration/reverse osmosis with varying water chemistry

Cited by 66 publications

References 52 publications

Removal of Naturally Occurring Strontium by Nanofiltration/Reverse Osmosis from Groundwater

Removal of Naturally Occurring Strontium by Nanofiltration/Reverse Osmosis from Groundwater

Fluoride Polluted Groundwaters in Calabria Region (Southern Italy): Natural Source and Remediation

Synthesis and characterization of aluminum-based adsorbent and application in fluoride removal from aqueous solution

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