scholarly journals Novel Lanthanum Doped Magnetic Teff Straw Biochar Nanocomposite and Optimization Its Efficacy of Defluoridation of Groundwater Using RSM: A Case Study of Hawassa City, Ethiopia

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Temesgen Abeto Amibo ◽  
Surafel Mustafa Beyan ◽  
Tsegaye Markos Damite
Keyword(s):  
Rotational Speed ◽  
Ligand Exchange ◽  
Contact Time ◽  
Adsorption Process ◽  
Quadratic Model ◽  
Fluoride Removal ◽  
Fluoride Ions ◽  
Removal Capacity ◽  
Mathematical Process

The problem extent of the large concentration of fluoride ions in drinking water is still a central health issue. In the present study, lanthanum doped magnetic Teff straw biochar (LDMTSB) was developed as a novel adsorbent for removing fluoride ions in the groundwater in Rift-Valley regions, especially Hawassa city, Ethiopia. The synthesized LDMTBC was characterized via FTIR, XRD, SEM, and BET. And, this analysis proposed that multiadsorption techniques such as ligand exchange, precipitations, and electrostatic interaction could be evinced throughout the fluoride ions adsorption process by LDMTSB. The constraints that influence the adsorption efficacy, namely, a dosage of LDMTSB, contact time, pH of the solution, and rotational speed, were analyzed and optimized using the response surface methodology approach. Under the optimum situations, LDMTSB dosage: 3.97 g, contact time: 56.36 min, rotational speed: 591.19 rpm, and pH: 3.968 demonstrate high efficacy of LDMTSB with 98.89% fluoride removal capacity. Further, the quadratic model (R2 = 0.9841) was designated for governing the mathematical process. The LDMTSB was successful in the removal of fluoride ions in the groundwater. This study provides a valuable economical solution for the application of Teff straw.

scholarly journals Optimization of regenerated bone char for fluoride removal in drinking water: a case study in Tanzania

2006 ◽  
Vol 4 (1) ◽  
pp. 139-147 ◽  
Author(s):  
M. E. Kaseva
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Drinking Water ◽  
Contact Time ◽  
Fluoride Removal ◽  
Bone Char ◽  
Removal Capacity ◽  
Maximum Value ◽  
The World

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.

scholarly journals Penyisihan Fluoride dan COD Air Limbah Industri Asam Fosfat Menggunakan Kombinasi Presipitasi dan Elektrokoagulasi

METANA ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 47-54
Author(s):  
Adhi Setiawan ◽  
Nadya Ayu Arianingtyas ◽  
Novi Eka Mayangsari ◽  
Tanti Utami Dewi
Keyword(s):  
Removal Efficiency ◽  
Contact Time ◽  
Supply Voltage ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Precipitation Process ◽  
Fluoride Removal ◽  
Power Supply Voltage ◽  
Fluoride Ions ◽  
Electric Voltage

Proses produksi asam fosfat menghasilkan air limbah dengan kandungan fluoride dan Chemical Oxygen Demand (COD) yang berpotensi mencemari lingkungan jika tidak diolah secara tepat. Kandungan ion fluoride di dalam air dapat menjadi ancaman serius bagi kesehatan manusia karena menyebabkan kerusakan pada gigi dan tulang. Kombinasi presipitasi dan elektrokoagulasi merupakan salah satu alternatif yang efektif untuk menurunkan kandungan fluoride dan COD. Penelitian ini bertujuan menganalisis pengaruh pH presipitasi, tegangan, dan waktu kontak terhadap penyisihan fluoride dan COD pada limbah industri fosfat menggunakan metode presipitasi dan elektrokoagulasi. Proses presipitasi dan elektrokoagulasi dilakukan secara batch. Presipitan menggunakan bahan berupa Ca(OH)2 sedangkan proses elektrokoagulasi menggunakan elektroda aluminium yang tersusun secara monopolar. Pengaturan pH presipitasi menggunakan pH 5, 7, dan 9. Elektrokoagulasi menggunakan variasi waktu kontak 40, 50, dan 60 menit. Variasi tegangan listrik 17, 22, dan 27 V. Hasil penelitian menunjukkan bahwa peningkatan pH meningkatkan efisiensi penyisihan pada proses presipitasi. Peningkatan nilai tegangan listrik dan waktu kontak menyebabkan peningkatan efisiensi penyisihan fluoride dan COD. Efisiensi tertinggi pada proses penyisihan fluoride dan COD diperoleh pada kondisi pH 9, waktu kontak 60 menit dan tegangan 27 volt dengan nilai efisiensi penyisihan fluoride sebesar 99,84% dan efisiensi penyisihan COD sebesar 56,35%. The production process of phosphoric acid produces wastewater containing fluoride and COD which has the potential to pollute the environment if not treated properly. The content of fluoride ions in water can be a serious threat to human health because it causes damage to teeth and bones. The combination of precipitation and electrocoagulation is an effective alternative to reduce fluoride and COD content. This study aims to analyze the effect of pH of precipitation, voltage, and contact time on fluoride and COD removal in industrial phosphate waste using precipitation and electrocoagulation methods. The precipitation and electrocoagulation processes are carried out in batches. Precipitant uses a material in the form of Ca (OH) 2, while the electrocoagulation process uses aluminum electrodes that are arranged monopolarly. Setting the pH of the precipitation using pH 5, 7, and 9. Electrocoagulation using a variation of contact time 40, 50, and 60 minutes. Electric voltage variations 17, 22, and 27 V. The results showed that increasing pH increased the removal efficiency in the precipitation process. Increasing the value of the power supply voltage and contact time led to an increase in the efficiency of fluoride and COD removal. The highest efficiency in fluoride and COD removal process was obtained at conditions of pH 9, contact time of 60 minutes and a voltage of 27 volts with a fluoride removal efficiency value of 99.84% and COD removal efficiency of 56.35%.

scholarly journals Comparative Study on Adsorptive Characteristics of Diazinon and Chlorpyrifos from Water by Thermosensitive Nanosphere Polymer

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Faranak Pishgar ◽  
Homayon Ahmad Panahi ◽  
Ali Akbar Khodaparast Haghi ◽  
Vahid Motaghitalab ◽  
Amir Hesam Hasani
Keyword(s):  
Kinetic Data ◽  
Contact Time ◽  
Adsorption Process ◽  
Intraparticle Diffusion ◽  
Initial Concentration ◽  
Intraparticle Diffusion Model ◽  
First Order ◽  
Removal Capacity ◽  
Pseudo Second Order ◽  
Pseudo First Order

Diazinon and chlorpyrifos are two common organophosphorus poisons to fight the pests in Iran. The removal of these poisons from water by thermosensitive nanosphere polymer (TNP), synthesized from the copolymerization of N-isopropylacrylamide and 3-allyloxy-1,2-propanediol, was investigated. The effect of pH, contact time, and the initial concentration on the removal amount was studied. The highest removal amount of these poisons by TNP occurred at pH 7. The contact time increase improves the removal amount and the equilibrium contact time for diazinon and chlorpyrifos was 10 and 18 min, respectively. For low concentration of less than 50 mgL−1it was shown that removal capacity remains above 95%. The initial concentration above 50 mgL−1decreased the removal amount, in which chlorpyrifos showed a greater decrease. The kinetic data has been checked using pseudo first-order, pseudo second-order, and intraparticle diffusion equations. The intraparticle diffusion model had the best conformability for the adsorption process.

scholarly journals Removal of Fluoride in Water with Mexican Natural Zeolite

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1470 ◽  
Author(s):  
Javier Sampedro-Duran ◽  
Miguel Torres-Rodríguez ◽  
Mirella Gutiérrez-Arzaluz ◽  
Violeta Mugica-Álvarez
Keyword(s):  
Adsorption Process ◽  
Fixed Bed ◽  
Fluoride Removal ◽  
Surface Chemical ◽  
Fluoride Ions ◽  
Fixed Bed Column ◽  
Surface Chemical Composition ◽  
Column System ◽  
Eds Analysis ◽  
Ftir Characterization

This work presents the results of the fluoride removal in water, through an adsorption process with the use of a natural Mexican zeolite conditioned with calcium, manganese or iron in a fixed bed column system. The XRD and FTIR characterization results demonstrated that the conditioning modifies the surface chemical composition of the zeolite and the SEM/EDS analysis corroborates the increase of the exchanged ions. The conditioning of the zeolite generated an increase in the adsorption capacity of fluorine, the best percentage of removal obtained from fluoride ions was 98%, for a water with a concentration of 10 mg·L−1 with the conditioned zeolite with iron.

Chromium Removal from Aqueous Solution by Microwave-Modified Phosphogypusum

2014 ◽  
Vol 955-959 ◽  
pp. 16-20 ◽  
Author(s):  
Ping Ning ◽  
Lei Shi ◽  
Yue Hong Yang ◽  
Yang Cheng
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Adsorption Process ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Freundlich Model ◽  
Chromium Vi ◽  
Removal Capacity ◽  
Ph Range ◽  
Best Fit

The removal of chromium (VI) ions from aqueous solution by microwave-modified phosphogypsum was studied. The removal capacity of microwave-modified phosphogypsum for chromium (VI) ions was examined as a function of solution pH, contact time, adsorbent dosage. Before a series of the adsorption studies, phosphogypsum was pre-conditioned with microwave. It was observed that the adsorption of the chromium (VI) ions onto the phosphogypsum in the pH range of 2 and 11. The chromium (VI) adsorption process was described with the Langmuir and Freundlich theories, and the Freundlich model indicated the best fit to the adsorption process. Maximum adsorption capacity of microwave-modified phosphogypsum was found to be 3.126 mg g−1. The results proved that the microwave-modified phoshogypsum is a suitable adsorbent for the removal of chromium (VI) ions from aqueous solution.

Development and Comparative Analysis of Aluminosilicate Based Ceramic Filters for Ground Water Defluoridation

2014 ◽  
Vol 936 ◽  
pp. 822-828 ◽  
Author(s):  
Johnson Kwame Efavi ◽  
Abu Yaya ◽  
Solomon Adeborna ◽  
Julius Fobil
Keyword(s):  
Ground Water ◽  
Contact Time ◽  
Dental Fluorosis ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Fluoride Ions ◽  
Ceramic Filters ◽  
Low Levels ◽  
Filter Thickness ◽  
Time Required

Low levels of fluoride in drinking water is healthy for the teeth enamel, however, higher concentrations result in dental fluorosis with prolonged exposures leading to skeletal fluorosis. Fluoride removal capacities of ceramic filters using aluminosilicates (Anfoega clay, Kibi kaolin, Laterite soil and Termitaria earth) samples from Ghana Geological Survey Department have been investigated and analysed for possible application in the Bongo District of Ghana noted forhavinghigh fluoride concentration in its ground water. Batch sorption studies conducted revealed that the amount of fluoride ions removed increased proportionally with increasing filter thickness, temperature and contact time to an optimum value. Using particle size ranges of <355μm and 1cm filter thickness at room temperature, the percentage of fluoride removed by the samples reached an optimum value after 70mins. Increases in filter thickness, contact time or temperatureincreased the amount of fluoride ions removedand the time required to reach the optimum value reduced significantly.

The Adsorption of Cadmium Ions on Fly Ash Based Geopolymer Particles

2018 ◽  
Vol 766 ◽  
pp. 65-70 ◽  
Author(s):  
Sujitra Onutai ◽  
Takaomi Kobayashi ◽  
Parjaree Thavorniti ◽  
Sirithan Jiemsirilers
Keyword(s):  
Fly Ash ◽  
Removal Efficiency ◽  
Contact Time ◽  
Adsorption Process ◽  
Coal Fly Ash ◽  
Bet Surface Area ◽  
Cadmium Ions ◽  
Initial Concentration ◽  
Removal Capacity ◽  
Waste Coal

Geopolymer particles from waste coal fly ash were prepared in order to investigate adsorption process of Cadmium ions. The aim of the study is to focus on factors which affect adsorption process of heavy metals on geopolymer materials. The raw fly ash was mixed with sodium hydroxide solution and sodium silicate solution. After that geopolymer was cured at 80 °C for 24 hr. The sample was ground and washed until pH=7. The obtained geopolymer particles were dried at 60 oC. The raw materials and geopolymer were characterized. The XRD results showed a highly amorphous structure in obtained geopolymer. The major components of waste coal fly ash and synthesized geopolymer were SiO2, Al2O3, Fe2O3 and CaO. The BET surface area of fly ash and geopolymer particles were 0.83 m2/g and 85.01 m2/g, respectively. The adsorption conditions (initial concentration from 10-120 mg/L, temperature at 25-45 °C, pH of cadmium ions solution from 1-5, 0.02-0.14 g. of geopolymer and contact time for 5-180 min) were studied. From removal efficiency results, synthesized geopolymer had high removal capacity for cadmium ions (Cd2+). At pH 5 of solution, the highest Cd2+ removal capacity was obtained. In addition, the removal efficiency increases with an increasing geopolymer dosage, contact time and a decreasing of Cd2+ initial concentration. Moreover, both Langmuir and Freundlich models were investigated for studying adsorption isotherm. The result showed Langmuir model is more suitable for geopolymer adsorption of cadmium ion in aqueous solution than Freundlich model.

scholarly journals Removal of Fluoride Ions by Adsorption onto Fe2O3 /Areca Nut Activated Carbon Composite

2017 ◽  
Vol 12 (1) ◽  
pp. 175-183 ◽  
Author(s):  
Sahira Joshi ◽  
Mandira Adhikari Pradhananga
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Contact Time ◽  
Chemical Activation ◽  
Carbon Composite ◽  
Fluoride Removal ◽  
Batch Adsorption ◽  
Areca Nut ◽  
Fluoride Ions ◽  
Adsorbent Dose

The possibility of Fe2O3/Areca nut activated carbon composite as an adsorbent for removal of fluoride from water is presented. Activated carbon (AC) was prepared from Areca nut by chemical activation with phosphoric acid at 400°C under nitrogen atmosphere. The resultant AC was characterized by adsorption of methylene blue and iodine. As indicated by iodine and methylene blue adsorption, the AC was highly micro and meso porous in nature. The adsorbent was prepared by compositing the AC with ferric oxide. Batch adsorption experiments were conducted to describe the effect of pH, contact time and adsorbent dose on fluoride removal from water. Percentage removal of fluoride by the adsorbent was ~75 % at contact time of 180 minutes. The maximum adsorption of fluoride was observed at pH 2 with adsorbent dose of 20 gm/L. The adsorption equilibrium data was analyzed by Langmuir and Freundlich adsorption isotherms. The adsorption data was fitted Langmuir better than Freundlich isotherm. The adsorption capacity of the Fe2O3/Areca nut activated carbon composite was found to be 4.8 mg/gm. The composite adsorbent prepared from Areca nut AC could be an efficient adsorbent for removal of fluoride from water.Journal of the Institute of Engineering, 2016, 12(1): 175-183 

Utilisation of Biomass and Hybrid Biochar from Elephant Grass and Low Density Polyethylene for the Competitive Adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) from Aqueous Media

2020 ◽  
Vol 13 ◽  
Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Contact Time ◽  
Competitive Adsorption ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Polluted Water ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Elephant Grass

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.

scholarly journals Full Factorial Design for Gold Recovery from Industrial Solutions

Toxics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 111
Author(s):  
Maria Mihăilescu ◽  
Adina Negrea ◽  
Mihaela Ciopec ◽  
Petru Negrea ◽  
Narcis Duțeanu ◽  
...  
Keyword(s):  
Factorial Design ◽  
Adsorption Capacity ◽  
Contact Time ◽  
Adsorption Process ◽  
Design Method ◽  
Precious Metals ◽  
Gold Recovery ◽  
Maximum Adsorption Capacity ◽  
Gold Concentration ◽  
Commercial Resin

Gold is one of the precious metals with multiple uses, whose deposits are much smaller than the global production needs. Therefore, extracting maximum gold quantities from industrial diluted solutions is a must. Am-L-GA is a new material, obtained by an Amberlite XAD7-type commercial resin, functionalized through saturation with L-glutamic acid, whose adsorption capacity has been proved to be higher than those of other materials utilized for gold adsorption. In this context, this article presents the results of a factorial design experiment for optimizing the gold recovery from residual solutions resulting from the electronics industry using Am-L-GA. Firstly, the material was characterized using atomic force microscopy (AFM), to emphasize the material’s characteristics, essential for the adsorption quality. Then, the study showed that among the parameters taken into account in the analysis (pH, temperature, initial gold concentration, and contact time), the initial gold concentration in the solution plays a determinant role in the removal process and the contact time has a slightly positive effect, whereas the pH and temperature do not influence the adsorption capacity. The maximum adsorption capacity of 29.27 mg/L was obtained by optimizing the adsorption process, with the control factors having the following values: contact time ~106 min, initial Au(III) concentration of ~164 mg/L, pH = 4, and temperature of 25 °C. It is highlighted that the factorial design method is an excellent instrument to determine the effects of different factors influencing the adsorption process. The method can be applied for any adsorption process if it is necessary to reduce the number of experiments, to diminish the resources or time consumption, or for expanding the investigation domain above the experimental limits.

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