scholarly journals An investigation on the efficiency of low-cost adsorbents in removing uranium from water samples

2020 ◽  
Vol 10 (10) ◽  
Author(s):  
Sandeep Police ◽  
Sukanta Maity ◽  
Dilip Kumar Chaudhary ◽  
Sanjay Kumar Sahu ◽  
A. Vinod Kumar

Abstract The groundwater samples were found to be contaminated with high concentrations of uranium (U) in Punjab state as well as in few other locations of India. U being chemically toxic can deteriorate health when ingested. Hence, there is a need to remove U from contaminated water using an efficient, cheap and user friendly method. A study was initiated to investigate the efficiency of low-cost adsorbents in removing U from water. Seven adsorbents were screened for U removal efficiency, among which fly ash (FA) and tea waste (TW) were found to have better removal efficiency. Solid–liquid contact time and solution pH were optimized to establish conditions for better U removal efficiency. The U adsorption on FA and TW followed pseudo-second-order kinetics with rate constant values 4.63 g/mg/min and 15.63 g/mg/min, respectively. FA and TW had the highest U removal capability at pH 6 and pH 4, respectively. The U sorption data were fitted with Freundlich and Dubinin–Radushkevich isotherm models. The U adsorption on FA and TW is found to be a physical process with mean free energy (E) values less than 8 kJ/mol. Theoretically calculated maximum adsorption capacity values indicate that FA is a better adsorbent as compared to TW, which has been further confirmed experimentally. The U adsorption on both the adsorbents has interference from Ca2+ and no interference from Fe3+ at tested U concentrations. It is also found that FA and TW are effective in decontaminating U from spiked real groundwater samples to below the WHO (Guidelines for drinking water quality, 4th ed, vol 1, World Health Organization, Geneva, 2011) limit.

MRS Advances ◽  
2018 ◽  
Vol 3 (36) ◽  
pp. 2109-2118
Author(s):  
Erick Mobegi ◽  
Mildred Nawiri ◽  
Dickson Andala

ABSTRACTFluoride levels in drinking water exceeding 1.5 mg/L especially underground water can be detrimental to health. Various defluoridation technologies exist such as reverse osmosis, adsorption and ion exchange. However, adsorption has been preferred over the other due to its low cost and ease of operation. In this study, a novel adsorbent nanomaterial was prepared to remove fluoride from drinking water. The influence of different parameters such as pH, contact time, co-existing ions and dosage were investigated in order to understand the sorption behaviour of the adsorbent under varying conditions. The adsorption process best fitted with the Langmuir model with a maximum adsorption capacity of 62.5 mg/g. The adsorbent can be used under normal water pH=7. Anions and cations had no influence on the sorption capacity except for chlorides, carbonates and bicarbonates. The adsorbent reduced fluoride concentration from 10 ppm to approximately 1.5 ppm per 50 mg nanocomposite loading as recommended by World Health Organization. The synthesized nanocomposite can be used for defluoridation of water with high fluoride concentrations beyond recommended limit.


2017 ◽  
pp. 307-314
Author(s):  
Vesna Vucurovic ◽  
Vladimir Puskas ◽  
Uros Miljic

A simple, low cost, and effective method for the removal of acridine orange (AO), a mutagenic cationic dye, from aqueous model solutions by adsorption onto dried sugar beet pulp (SBP) was evaluated in the present study. The AO removal was enhanced along with the increase of the initial solution pH and dye concentration. It was found that the adsorption process closely follows a pseudo-second-order chemisorption kinetics. The obtained equilibrium data obey both the Freundlich and Langmuir isotherm models. The SBP was proved to be very promising adsorbent for AO removal. Maximum adsorption capacity of the Langmuir monolayer of SBP for AO was found to be 5.37, 34.6, 89.62, 144.53 and 324.58 mg/g, at 25?C for the solution pH of 2, 4, 5, 6, and 8, respectively.


2020 ◽  
Vol 10 (20) ◽  
pp. 7237 ◽  
Author(s):  
Mokhtar Ali Amrani ◽  
Atef M. Ghaleb ◽  
Adham E. Ragab ◽  
Mohamed Z. Ramadan ◽  
Tamer M. Khalaf

Arsenite (As(III)) and Selenate (Se(VI)) are universally touted as extremely toxic oxyanions in natural and industrial water systems. Thus, the production of low-cost adsorbents that are scalable and toxic-free is of great importance today. In this work, a large-scale goethite nanorods (α-FeOOH NRs) is synthesized using a modified rapid hydrolysis method. The obtained powder is characterized using different multidisciplinary techniques. Accordingly, the results showed uniform and straight nanorods (length ~400 nm and diameter ~40 nm) resembling cigar-like morphology while the structure is confirmed to be of orthorhombic α-FeOOH phase. The potential application of this material to adsorb As (III) and Se (VI) ions in water is explored. In particular, for initial adsorbate concentrations (~500 µg/L), the removal efficiencies are found exceptional with α-FeOOH doses of 0.33 g/L and ~0.5 g/L for As (III) and Se (VI), respectively. Attractively, the adsorption capacities were estimated using trusted isotherms and then experimentally verified at ultimately high concentrations. Besides, a pH-controlled adsorption study showed that a pH of 5–8 is a favored range for higher ionic uptake, which meets the World Health Organization (WHO) benchmarks of drinking water. To conclude, the α-FeOOH NRs are potential adsorbent for the sustainable removal of toxin ions in water systems.


2018 ◽  
Vol 8 (2) ◽  
pp. 70
Author(s):  
Nina Ariesta ◽  
Risansyah Rifansyah ◽  
Dian Arrisujaya ◽  
Mamay Maslahat

Velvet Apple Fruit Seeds (Diospyros blancoi) as Biosorbent of Cr(III)          Velvet Apple Fruit (Diospyros blancoi) has not been explored more in Indonesia. The purpose of research was to explore the use of Velvet Apple Fruit seeds as adsobent of Cr(III) in waste. Biosorbent of velvet apple fruit seeds in removing Cr (III) metal ions has been investigated using batch method. Several parameters were used to determine absorption optimum conditions such as solution pH, contact time and biosorbent dosage. Langmuir, Freundlich and Temkin isotherm models were used in determining biosorption equilibrium. FTIR and SEM-EDX were used to characterize the velvet apple fruit seeds biosorbent. The equilibrium adsorption isotherms showed the velvet apple fruit seeds biosorbent had a maximum adsorption capacity of 5.592 mg/g. The adsorption efficiency of Cr (III) ion by velvet apple fruit seeds was 81.78%. The results showed that velvet apple fruit seeds potentially as an alternative low-cost biosorbent for removing heavy metal ions in solution.Keywords: biosorption, heavy metals, alternative biosorbent, waste water treatmentABSTRAK          Buah bisbul di Indonesia belum tereksplor dengan baik potensinya. Tujuan penelitian adalah untuk megetahui potensi biji buah Bisbul sebagai adsorben logam Cr(III) pada limbah. Biosorben biji buah bisbul (Diospyros blancoi) dalam menyerap ion logam Cr(III) telah diteliti dengan menggunakan metode batch. Beberapa parameter digunakan untuk menentukan kondisi optimum penyerapan seperti pH larutan, waktu kontak dan dosis biosorben. Model isoterm Langmuir, Freundlich dan Temkin dipakai dalam menentukan kesetimbangan biosorpsi. FTIR dan SEM-EDX digunakan dalam mengkarakterisasi biosorben biji buah bisbul. Isoterm adsorpsi kesetimbangan menunjukkan biosorben biji buah bisbul mempunyai kapasitas adsorpsi maksimum 5,592 mg/g. Efisiensi penyerapan ion Cr(III) oleh biji buah bisbul mencapai 81,78%. Hasil penelitian menunjukkan bahwa biji buah bisbul berpotensi sebagai alternatif biosorben murah dalam menghilangkan ion logam berat dalam larutan.Kata kunci: biosorpsi, logam berat, alternatif biosorben, pengolahan air limbah


Author(s):  
Mazen K. Nazal ◽  
Durga Rao ◽  
Nabeel Abuzaid

Abstract Emerging contaminants such as pharmaceutical compounds have potential hazards to the aquatic environment and human health. In this paper, the adsorptive removal of the drug Nitrazepam from water was investigated for the first time using biochar prepared from Sargassum macroalgae. The removal efficiency of Nitrazepam using 1 g/L of Sargassum macroalgae-derived biochar was 98% with a maximum adsorption capacity of 143.12 mg/g. Effects of solution pH, adsorbent mass, adsorbate concentration, contact time and temperature on the removal of Nitrazepam were investigated. Different adsorption isotherms and kinetics were also tested. It was found that the solution pH slightly influenced the removal efficiency. The adsorption data fit the Freundlich isotherm model and the adsorption process of Nitrazepam onto Sargassum macroalgae-derived biochar is spontaneous, endothermic and followed the pseudo-second-order kinetics. Based on this work, it was determined that the low-cost Sargassum macroalgae-derived biochar adsorbent could be a promising adsorbent to remove Nitrazepam from water effectively.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xuan Hoa Vu ◽  
Lan Huong Nguyen ◽  
Huu Tap Van ◽  
Dinh Vinh Nguyen ◽  
Thu Huong Nguyen ◽  
...  

In this study, freshwater snail shells (FSSs) containing CaCO3 were used as a low-cost biosorbent for removing Cr(VI) from aqueous solutions. The characteristics of FSS and mechanism of Cr(VI) adsorption onto FSS were investigated. The FSS biosorbent was characterized using nitrogen adsorption/desorption isotherm, X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The adsorption mechanism was determined by conducting various batch adsorption experiments along with fitting experimental data with various adsorption models. Batch adsorption experiments were conducted as a function of solution pH, contact time, biosorbent dose, and initial Cr(VI) concentration. Results indicated that pH = 2, a contact time of 120 min, and an initial Cr(VI) concentration of 30 mg/L at 20°C were the best conditions for adsorption of Cr(VI) onto FSS. The Cr(VI) adsorption onto FSS decreased with an increase in temperature from 20 to 40°C. The obtained maximum adsorption capacity was 8.85 mg/g for 2 g/L of FSS dose with 30 mg/L of initial Cr(VI) at 20°C. The adsorption equilibrium data fit well with the Sips and Langmuir isotherm models at 20°C with a high R2 of 0.981 and 0.975, respectively. Also, a good correlation between the experimental data and the pseudo-second-order model was achieved, with the highest R2 of 0.995 at 20°C. The adsorption mechanisms were electrostatic interaction and ion exchange. Simultaneously, this mechanism was also controlled by film diffusion. The Cr(VI) adsorption process was irreversible, spontaneous (−∆G°), exothermic (∆H° is negative), and less random (∆S° is negative). In conclusion, freshwater snail shells have the potential as a renewable adsorbent to remove toxic metals from wastewater.


2020 ◽  
Vol 3 (1) ◽  
pp. 22-36 ◽  
Author(s):  
Shankar Karuppannan ◽  
Nafyad Serre Kawo

Assessment of groundwater quality is vital for the sustainable use of the resources for domestic and agricultural purposes. In this study spatial variation of physicochemical parameters were analyzed for Northeast Adama Town. Water Quality Index (WQI) and irrigation indices were used to determine the suitability of groundwater for drinking and irrigation purposes, respectively. Further, the physical-chemical results were compared with the Ethiopian standards and the World Health Organization (WHO) standards for drinking and public health. Using GIS interpolation methods in Arc GIS 10.3.1, spatial distribution maps of pH, TDS, EC, Cl−, HCO32−, SO42−, Ca2+, Mg2+, Na+ and K+, RSC, SAR, Na% were prepared. Results indicated that except ASTU well 2, all samples are below the desirable limits of WHO. The WQI results indicated that 85% of samples and 15% of samples were in good and poor categories, respectively. Irrigation indices show that the most groundwater samples have excellent water classes, indicating that they are suitable for irrigation purposes.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3718
Author(s):  
Mohammad Azam ◽  
Saikh Mohammad Wabaidur ◽  
Mohammad Rizwan Khan ◽  
Saud I. Al-Resayes ◽  
Mohammad Shahidul Islam

The aim of the research was to prepare low-cost adsorbents, including raw date pits and chemically treated date pits, and to apply these materials to investigate the adsorption behavior of Cr(III) and Cd(II) ions from wastewater. The prepared materials were characterized using SEM, FT-IR and BET surface analysis techniques for investigating the surface morphology, particle size, pore size and surface functionalities of the materials. A series of adsorption processes was conducted in a batch system and optimized by investigating various parameters such as solution pH, contact time, initial metal concentrations and adsorbent dosage. The optimum pH for achieving maximum adsorption capacity was found to be approximately 7.8. The determination of metal ions was conducted using atomic adsorption spectrometry. The experimental results were fitted using isotherm Langmuir and Freundlich equations, and maximum monolayer adsorption capacities for Cr(III) and Cd(II) at 323 K were 1428.5 and 1302.0 mg/g (treated majdool date pits adsorbent) and 1228.5 and 1182.0 mg/g (treated sagai date pits adsorbent), respectively. It was found that the adsorption capacity of H2O2-treated date pits was higher than that of untreated DP. Recovery studies showed maximal metal elution with 0.1 M HCl for all the adsorbents. An 83.3–88.2% and 81.8–86.8% drop in Cr(III) and Cd(II) adsorption, respectively, were found after the five regeneration cycles. The results showed that the Langmuir model gave slightly better results than the Freundlich model for the untreated and treated date pits. Hence, the results demonstrated that the prepared materials could be a low-cost and eco-friendly choice for the remediation of Cr(III) and Cd(II) contaminants from an aqueous solution.


2021 ◽  
Vol 11 (8) ◽  
pp. 3495
Author(s):  
Shabir Hussain ◽  
Yang Yu ◽  
Muhammad Ayoub ◽  
Akmal Khan ◽  
Rukhshanda Rehman ◽  
...  

The spread of COVID-19 has been taken on pandemic magnitudes and has already spread over 200 countries in a few months. In this time of emergency of COVID-19, especially when there is still a need to follow the precautions and developed vaccines are not available to all the developing countries in the first phase of vaccine distribution, the virus is spreading rapidly through direct and indirect contacts. The World Health Organization (WHO) provides the standard recommendations on preventing the spread of COVID-19 and the importance of face masks for protection from the virus. The excessive use of manual disinfection systems has also become a source of infection. That is why this research aims to design and develop a low-cost, rapid, scalable, and effective virus spread control and screening system to minimize the chances and risk of spread of COVID-19. We proposed an IoT-based Smart Screening and Disinfection Walkthrough Gate (SSDWG) for all public places entrance. The SSDWG is designed to do rapid screening, including temperature measuring using a contact-free sensor and storing the record of the suspected individual for further control and monitoring. Our proposed IoT-based screening system also implemented real-time deep learning models for face mask detection and classification. This module classified individuals who wear the face mask properly, improperly, and without a face mask using VGG-16, MobileNetV2, Inception v3, ResNet-50, and CNN using a transfer learning approach. We achieved the highest accuracy of 99.81% while using VGG-16 and the second highest accuracy of 99.6% using MobileNetV2 in the mask detection and classification module. We also implemented classification to classify the types of face masks worn by the individuals, either N-95 or surgical masks. We also compared the results of our proposed system with state-of-the-art methods, and we highly suggested that our system could be used to prevent the spread of local transmission and reduce the chances of human carriers of COVID-19.


2018 ◽  
Vol 19 (4) ◽  
pp. 1066-1072
Author(s):  
Q. H. Jin ◽  
C. Y. Cui ◽  
H. Y. Chen ◽  
Y. Wang ◽  
J. F. Geng ◽  
...  

Abstract Adsorption (ADS) and dielectrophoresis (DEP) techniques were combined (ADS/DEP) to efficiently remove As(V) in industrial wastewater. Fly ash, activated carbon, corncob and plant ash were tested to determine the best adsorbent by their adsorption capacity. Plant ash showed the highest adsorption capacity compared with the others. Different parameters such as solution pH and adsorbent dose were explored. The maximum As(V) removal efficiency was 91.4% at the optimized conditions (pH 9.0, adsorbent dose 5 g/L) when the initial concentration of As(V) was 15 mg/L. With the ADS/DEP technique, the plant ash particles with adsorbed As(V) were trapped on the electrodes in a DEP device. The ADS/DEP process could increase the removal efficiency of As(V) to 94.7% at 14 V even when the initial concentration of As(V) was 15 mg/L. And the residual concentration of As(V) decreased to 0.34 mg/L after two series of the ADS/DEP process. The adsorbents before and after DEP were examined by scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis. After the DEP process, the weight percentage of As(V) on the adsorbent surface increased to 0.96% from 0.5%. The ADS/DEP process could be a new efficient way to remove arsenic pollutant at high concentrations.


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