Use Of Bone Char Research Articles

Mitigation of Fluoride Contamination in Drinking Water Supply Sources by Adsorption Using Bone Char: Effects of Mineral and Organic Matrix

This study focused on fluoride (F−) contamination of water sources in Bahimi village, Cameroon. After the first investigation, results revealed that all water samples collected had elevated concentrations of fluoride ions (2.3 ± 0.1) mg/L to (4.5 ± 0.2) mg/L above the WHO guidelines (less than 1.5 mg/L). To mitigate the F− levels, the use of bone char (BC) as an adsorbent material was proposed and its performance was tested. BC was prepared from bovine bones at different calcination temperatures (350 °C, 450 °C, 550 °C and 650 °C) and residence times (1 h and 2 h). The prepared materials were characterized in detail by SEM/EDS, BET, FTIR, and XRD. The BET findings indicated that the surface area of BC samples decreased with increasing calcination temperature and residence time. At a lower heating temperature and holding time (350 °C, 1 h), the prepared BC exhibited a higher specific surface area (112.3 ± 0.3) m2/g and adsorption capacity for F− in the sampled water. Also, the batch adsorption experiments showed that the optimized adsorbent dose of 8 g/L facilitates the reduction in the F− level of the sampled water below the acceptable limit level (1.5 mg/L) within 5 min of treatment. The presence of Ca2+ and Mg2+ in natural water has a positive effect on the removal of F− in BC resulting in a high adsorption performance range of (72.5 ± 1.4)% to (80.3 ± 0.6)%. It was found that the adsorption of Ca2+ on the BC surface occurs via cation exchange with Na+. However, an increase in dissolved organic carbon (DOC) in the treated water limited the application of BC. Overall, the study presented a cost-effective adsorbent for the removal of this recalcitrant ion in the water source.

Modelling of manganese-contaminated groundwater through batch experiments: Implications for bone char remediation

In this study, bone char was successfully produced by the thermal pyrolysis of cattle bones at 450 °C using a locally designed double barrel retort drum. The bone char was characterised by the point of zero charge, scanning electron microscopy/energy dispersive x-ray, Fourier-transform infrared, and Brunauer-Emmett-Teller analysis. Manganese (II) contaminated groundwater and laboratory-prepared aqueous manganese solutions were treated with the prepared bone char. Modelling of the manganese (II) remediation of the natural groundwater by cattle bone char was investigated for its application to water quality. Adsorption kinetics and investigations of the Freundlich and Langmuir model isotherms were part of the batch adsorption experiments that were utilised to evaluate the removal capabilities of the char under different metal concentrations, contact time, pH, and char dose. The thermodynamic variables showed that manganese (II) ions adsorption by the cattle bone char was an exothermic and spontaneous process. Regarding regression coefficients, the Freundlich isotherm model outperformed the Langmuir model in predicting the best match or fit for the adsorption data. The maximum removal rate of manganese (II) ions by the bone char in 60 min was estimated to be 99.2% under laboratory-controlled conditions. An amount of 0.515 mg/L of manganese (out of 0.645 mg/L) from natural groundwater was adsorbed on 1 g of 0.315 mm bone char, whereas 0.05 mm of the bone char adsorbed 0.639 mg/L manganese (II) ions. The use of bone char from cattle bones is an effective and sustainable solution for the treatment of manganese contamination of groundwater. The char of cattle bone can be utilised as a safe and environmentally acceptable adsorbent.

Enhancement of Releasing Phosphorus from Bone Char in Calcareous Sandy Soil Under Applying Different Levels of Water Salinity

The high cost of phosphate fertilizers, as well as pollution with heavy and radioactive elements, motivated us to find clean alternatives for phosphate fertilizers to conserve the environment such as bone char. Also, the groundwater used in the agricultural activity of desert soils is considered to be saline. Therefore, the specific objective of this incubation experiment was to investigate the application of bone char with different levels of water salinity on changes of phosphorus (P) availability and some soil quality indicators of calcareous sandy soil. The results of this study revealed that applying bone char (BC) combined with saline water significantly increased the available P (Olsen-P) in calcareous sandy soil compared to the control (unamended soil) and bone char with distilled water treatment. The P release from bone char increased with increasing water salinity levels. The increase of incubation time results in an increment of Olsen-P concentration at a high level of saline water. Soil pH values declined with the addition of bone char combined with saline water, while the electrical conductivity (EC) of the soil in this study increased gradually with increasing the water salinity level in the presence of bone char. The soluble sulfate (SO42−) increased by applying bone char and saline water. Based on this, we can suggest the use of bone char under the presence of saline water as an alternative to phosphate fertilizer, especially in sustainable agriculture because it is economically and environmentally friendly. The bone char can be a substitute for chemical fertilizers produced from rock phosphate.

Use of bone char prepared from an invasive species, pleco fish (Pterygoplichthys spp.), to remove fluoride and Cadmium(II) in water

In this study, bone char (BC) from pleco fish (Pterygoplichthys spp.) was synthesized, and their textural and physicochemical properties, as well as its adsorption capacity towards fluoride and Cd(II) from single and binary aqueous solutions, were determined. The results showed that the properties of the BCs were independent of the type of bone used and the surface areas were close to 110 m2 g−1. The effect of solution pH revealed that the adsorption capacity of BC towards fluoride from water raised by decreasing the solution pH. This trend was attributed to the electrostatic interaction between the positively charged surface and the fluoride in aqueous solution. On the contrary, the capacity of BC for adsorbing Cd(II) was enhanced by increasing the solution pH, indicating that electrostatic interactions were also essential but with a contrary effect in comparison with fluoride adsorption due to the negatively charged surface at pH above the point zero charge (pHPZC = 8.16). The experimental data for binary adsorption of fluoride and Cd(II) were interpreted satisfactorily using the modified Freundlich multicomponent isotherm (EFMI), and the experimental data revealed that Cd(II) have an antagonistic effect on the adsorption of fluoride, whereas the presence of fluoride does not affect the capacity of BC for adsorbing Cd(II). Thermogravimetric, XRD diffraction and IR spectroscopy analysis corroborated that the adsorption of fluoride in BC is due to electrostatic attractions, ion exchange or chemisorption and physisorption. Besides, the removal of Cd(II) occurs by physical adsorption and ion exchange. It was concluded that BC is an alternative material for the removal of fluoride and Cd(II) from aqueous solutions, and it is a possible application for using the bones of this invasive fish species.

Fixed-Bed Adsorption Comparisons of Bone Char and Activated Alumina for the Removal of Fluoride from Drinking Water

Fluoride is commonly found at elevated concentrations in groundwaters worldwide and is difficult to remove even with activated alumina (AA) adsorption, the best available technology. Consequently, alternative treatment technologies for fluoride removal continue to be researched, including the use of bone char (BC) adsorption. However, BC studies are limited mostly to batch or equilibrium studies, which can be difficult to extend to full-scale applications. Therefore, the goal of this study was to compare a BC to a commercial AA for treating groundwater with a naturally occurring fluoride concentration of 8.5 mg/L using pilot- and bench-scale fixed-bed adsorption tests. At the pilot scale using an empty bed contact time (EBCT) of 10 min, fluoride breakthrough reached 1.5 mg/L within 450 bed volumes (3.1 days) and 650 bed volumes (4.5 days) for BC and AA, respectively. Two designs of the rapid small-scale column test (RSSCT) were applied to simulate the pilot columns, where the proportional diffusivity RSSCT (PD-RSSCT) design provided a more adequate prediction of fluoride breakthrough to 1.5 mg/L. The PD-RSSCT was also used to evaluate BC and AA EBCTs of 10 and 20 min, with the longer EBCT providing no significant increase in adsorbent use efficiency. Complete BC regeneration using countercurrent flow to the PD-RSSCT was limited by exposure to the sodium hydroxide regenerant solution and, potentially, the presence of arsenic.

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

Since the realization in the 1930s that elevated fluoride concentrations in drinking water can have detrimental effects on human health, new methods have been progressively developed in order to reduce fluoride to acceptable levels. In the developing world the necessity for filtration media that are both low-cost and sourced from locally available materials has resulted in the widespread use of bone char. Since the early 1990s metallic iron (Fe0) has received widespread use as both an adsorbent and a reducing agent for the removal of a wide range of contaminant species from water. The ion-selectivity of Fe0 is dictated by the positively charged surface of iron (hydr)oxides at circumneutral pH. This suggests that Fe0 could potentially be applied as suitable filter media for the negatively charged fluoride ion. This communication seeks to demonstrate from a theoretical basis and using empirical data from the literature the suitability of Fe0 filters for fluoride removal. The work concludes that Fe0-bearing materials, such as steel wool, hold good promise as low-cost, readily available and highly effective decentralized fluoride treatment materials.

ADSORPTION OF MANGANESE FROM ACID MINE DRAINAGE EFFLUENTS USING BONE CHAR: CONTINUOUS FIXED BED COLUMN AND BATCH DESORPTION STUDIES

In the present study, continuous fixed bed column runs were carried out in an attempt to evaluate the feasibility of using bone char for the removal of manganese from acid mine drainage (AMD). Tests using a laboratory solution of pure manganese at typical concentration levels were also performed for comparison purposes. The following operating variables were evaluated: column height, flow rate, and initial pH. Significant variations in resistance to the mass transfer of manganese into the bone char were identified using the Thomas model. A significant effect of the bed height could only be observed in tests using the laboratory solution. No significant change in the breakthrough volume could be observed with different flow rates. By increasing the initial pH from 2.96 to 5.50, the breakthrough volume was also increased. The maximum manganese loading capacity in continuous tests using bone char for AMD effluents was 6.03 mg g-1, as compared to 26.74 mg g-1 when using the laboratory solution. The present study also performed desorption tests, using solutions of HCl, H2SO4, and water, aimed at the reuse of the adsorbent; however, no promising results were obtained due to low desorption levels associated with a relatively high mass loss. Despite the desorption results, the removal of manganese from AMD effluents using bone char as an adsorbent is technically feasible and attends to environmental legislation. It is interesting to note that the use of bone char for manganese removal may avoid the need for pH corrections of effluents after treatment. Moreover, bone char can also serve to remove fluoride ions and other metals, thus representing an interesting alternative material for the treatment of AMD effluents.

Reusing by‐products in agricultural fields

Reusing by‐products in agricultural fields

Homemade bone charcoal adsorbent for defluoridation of groundwater in Thailand

High levels of fluoride in groundwater are a significant environmental and health problem in Thailand, as in many parts of the world. Small household defluoridators have several advantages over centralized treatment systems. In Thailand, however, use of bone char for water treatment has met resistance because of objectionable taste and odours of the water produced and the social resistance to handling fresh bone. This paper presents a method that uses bone charcoal as an absorbent for removing fluoride from groundwater. The commercially provided boiled bone is burned in a simple homemade furnace that can be constructed, operated and maintained easily by small rural householders. The method to produce the Thai bone char eliminates the odour and objectionable taste and also does not require the user to handle fresh bone, thus eliminating the social resistance. To evaluate the efficacy of the absorbent, batch experiments compare Thai and Indian bone char. Sorption isotherms are fit to the Freundlich and Langmuir equations and the kinetics are modelled using the pseudo first-order Lagergren equation. Results show that the sorption characteristics of Thai bone char compare favourably with the Indian bone char, with approximately 80% of the fluoride removed in both cases.

Use of bone char as an adsorbent in preparation of water for dialysis.

Currently, deionizers (DI) and reverse osmosis (RO) are used to prepare water for dialysis. When water metal levels increase, for example, with the use of alum, the variation in metal content can reduce RO performance. Pretreatment of water with ethylenediaminetetraacetic acid or alkali can be used to reduce Al fouling. The authors examined adsorption of metal water contaminants with bone char (BRIMAC, Biolab, Oakville, Canada) as a cheaper alternative. Water treatment for the unit consists of a blend valve, 30 mu filter, 2 X 3 cu ft adsorption tanks, 5 mu filter, 30,000 grain automatic water softener, 5 mu filter, Millipore RO 1,000, 2 X 7" mixed bed DI in series, and a polysulfone ultrafilter. During 29 weeks of continuous bone char adsorption, raw water Al ranged from 0.022 to 0.298 ppm (mean, 0.097 +/- 0.075 ppm; cf. the Environmental Protection Agency's proposed drinking water standard of < 0.05 ppm). Postadsorption Al ranged from 0.002 to 0.076 ppm (0.041 +/- 0.04), a decrease of 55-91% (83.0 +/- 8.5%). Final water Al was < 0.001 at all times. No fouling of the RO membrane occurred. Residual chlorine after the first adsorption was < 0.02 to 0.09 ppm. Significant reductions in other metals, notably Pb, Cu, and Zn were noted. Bone char is a cheap, effective, and simple alternative for removing excess trace elements from water for hemodialysis. Further study to evaluate the efficacy of bone char in removing other organic and inorganic water contaminants is needed.