Study on Arsenic Removal in the Simulating Constructed Wetland

2013 ◽  
Vol 777 ◽  
pp. 386-389
Author(s):  
Jun Ying Zhao ◽  
Hua Ming Guo
Keyword(s):  
Constructed Wetland ◽  
Arsenic Removal ◽  
Early Stage ◽  
Arsenic Concentration ◽  
Pteris Vittata ◽  
Small Scale ◽  
Arsenic Content ◽  
Main Role ◽  
Batch Tests ◽  
Concentration Changes

Arsenic concentration changes in small-scale simulating constructed wetland composed with shale ceramic, zeolite, quartz sand andPteris vittatawere examined. During arsenic removal by the constructed wetlands, arsenic interception by the natural media played the main role in the early stage andPteris vittatauptake played the key role for arsenic removal in the later stable stage. When As (III) concentration in inflow was about 1 mg/L, the arsenic removal ratio by the two was between 22.2% and 66.6% and kept about 33% in the end. Arsenic average content in fronds and roots ofPteris vittataafter experiments were respectively 17610 and 2491 mg/kg. Transfer factor was 7.08. Compared with batch tests, arsenic content accumulated in plants increased significantly.

As(III) Removal by Dynamic Adsorption onto Amberlite XAD7 Functionalized with Crown Ether and Doped with Fe(III) Ions

2019 ◽  
Vol 70 (7) ◽  
pp. 2330-2334
Author(s):  
Mihaela Ciopec ◽  
Adina Negrea ◽  
Narcis Duteanu ◽  
Corneliu Mircea Davidescu ◽  
Iosif Hulka ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Fixed Bed ◽  
World Health ◽  
Arsenic Content ◽  
Arsenic Adsorption ◽  
Stage Of Development ◽  
Wide Range ◽  
Health Organization

Arsenic content in groundwater�s present a wide range of concentration, ranging from hundreds of micrograms to thousands of micrograms of arsenic per litter, while the maximum permitted arsenic concentration established by World Health Organization (WHO) is 10 mg L-1. According to the WHO all people, regardless of their stage of development and their social economic condition, have the right to have access to adequate drinking water. The most efficient and economic technique used for arsenic removal is represented by adsorption. In order to make this remediation technique more affordable and environmentally friendly is important to new materials with advance adsorbent properties. Novelty of present paper is represented by the usage of a new adsorbent material obtained by physical - chemical modification of Amberlite XAD polymers using crown ethers followed by iron doping, due to well-known affinity of arsenic for iron ions. Present paper aims to test the obtained modified Amberlite polymer for arsenic removal from real groundwater by using adsorption in a fixed bed column, establishing in this way a mechanism for the adsorption process. During experimental work was studied the influence of competing ions from real water into the arsenic adsorption process.

Using ZnO Nanorods Coated Porous Ceramic Monolith to Remove Arsenic from Groundwater

2017 ◽  
Vol 751 ◽  
pp. 756-765 ◽  
Author(s):  
Kannika Khwamsawat ◽  
Jukkrit Mahujchariyawong ◽  
Supamas Danwittayakul
Keyword(s):  
Water Sample ◽  
Arsenic Removal ◽  
Porous Ceramic ◽  
Zno Nanorods ◽  
Arsenic Concentration ◽  
Solution Concentration ◽  
Growth Time ◽  
Arsenic Content ◽  
Growth Solution ◽  
Nano Adsorbent

Arsenic contaminants in drinking water pose a threat to human health. In this study, we report the use of nanotechnology to enhance the efficiency of arsenic removal. In here, zinc oxide (ZnO) has been selected for this application due to its environmentally friendly to human being. One-dimensional ZnO nanorods were grown on porous ceramic substrate by hydrothermal technique. The monolith nano-adsorbents were investigated using field emission scanning electron microscope (FESEM, Hitachi, SE-8030), while phase compositions and specific surface area were examined by x-ray diffractometer (XRD, PAnalitical, X’Pert PRO). Experiments of arsenic adsorption were conducted by using 200 ppb arsenic concentration solution with a continuously stirring system. After the adsorption, each water sample was then measured the arsenic content by inductively coupled plasma-optical emission spectroscope (ICP-OES) as compare to the original water sample to calculate the percentage of arsenic removal. We found that morphology of nano-adsorbent on using the growth solution concentration of 20mM of growth solution concentration and 20 hours of growth time showed the highest density of ZnO hexagonal nanorods with about 100 nm in diameter. The optimization studies obtained 30 minute of adsorption time, pH as 7. This nano-adsorbent exhibited about 98% of arsenic removal. For the comparison with commercial adsorbent (As600), ZnO nano-adsorbent has a better efficiency. The strong competitive ion on the arsenic removal was PO43-. Moreover, the real groundwater after treatment doesn’t have any toxic residue. Therefore, ZnO nanorods coated on porous ceramic can be the candidate material for arsenic removal from groundwater.

scholarly journals Effect of different fertilizer types on Arsenic removal capacity of two fern species

2014 ◽  
Vol 6 (1) ◽  
pp. 42-46
Author(s):  
Thi Kim Anh Bui
Keyword(s):  
Environmental Factors ◽  
Plant Growth ◽  
Arsenic Removal ◽  
Organic Fertilizer ◽  
Arsenic Concentration ◽  
Pteris Vittata ◽  
Removal Capacity ◽  
Fern Species ◽  
Pityrogramma Calomelanos ◽  
Hyperaccumulator Plant

More and more attention has been paid to the research on phytoremediation and hyperaccumulators. Arsenic (As) uptake by hyperaccumulator plant species depends on many different environmental factors. Fertilizer is one of the most important factors because the plant growth needs nutrients. In this study, the pot experiments were conducted in 12 weeks to understand the effect of different fertilizer on As removal capacity of Pityrogramma calomelanos and Pteris vittata. The results showed that, Arsenic concentration in the frond is higher than that in the root of the fern. As removal efficiency of the ferns from the soil amended with both inorganic and organic fertilizer is highest. The ferns removed As content in soil up to 7.4 and 12.6 mg As per kg DW soil, respectively. For the control experiments without adding fertilizers, As removal ability of the ferns from the soil is lowest that was only 2.1 mg As per kg DW soil. Trên thế giới đã và đang có nhiều nghiên cứu, ứng dụng phương pháp sử dụng thực vật để xử lý ô nhiễm, đặc biệt là các loài thực vật siêu tích tụ kim loại nặng. Sự tích lũy Asen (As) trong các loài thực vật siêu tích lũy phụ thuộc vào rất nhiều yếu tố môi trường và dinh dưỡng khác nhau. Phân bón là một trong những yếu tố quan trọng nhất vì sự phát triển cây rất cần chất dinh dưỡng. Trong nghiên cứu này, các thí nghiệm được tiến hành trong 12 tuần để đánh giá về ảnh hưởng của các loại phân bón khác nhau đến khả năng xử lý ô nhiễm As trong đất của dương xỉ. Kết quả thu được cho thấy, nồng độ As tích lũy trong phần thân của dương xỉ cao hơn rất nhiều so với phần rễ của cây. Hiệu quả loại bỏ As ra khỏi đất của dương xỉ trong các thí nghiệm bổ sung cả phân bón vô cơ và phân bón hữu cơ là cao nhất. Pityrogramma calomelanos và Pteris vittata có thể loại bỏ hàm lượng As trong 1 kg trọng lượng khô đất tương ứng lên đến 7,4 và 12,6 mg. Các công thức thí nghiệm đối chứng không bổ sung phân bón thì cho hiệu quả loại bỏ As ra khỏi đất là thấp nhất chỉ 2,1 mg As trên 1 kg trọng lượng khô đất.

scholarly journals MERCURY AND ARSENIC CONTAMINATION FROM SMALL SCALE GOLD MINING ACTIVITIES AT SELOGIRI AREA, CENTRAL JAVA, INDONESIA

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Agung Harijoko ◽  
Tin May Htun ◽  
Rodhie Saputra ◽  
I Wayan Warmada ◽  
Lucas Donny Setijadji ◽  
...  
Keyword(s):  
Mercury Concentration ◽  
Arsenic Concentration ◽  
Arsenic Contamination ◽  
Stream Sediments ◽  
Dry Season ◽  
Small Scale ◽  
Arsenic Content ◽  
Mining Activities ◽  
Central Java ◽  
Dug Well

Small scale gold mines discussed here are located at Selogiri area, Central Java, Indonesia which was mined by local community mainly during gold rush in 1990s. This Selogiri gold deposit genetically is characterized by porphyry mineralization overprinted by epithermal system. The ore minerals assemblage consists of pyrite, sphalerite, chalcopyrite, galena, chalcocite and rare arsenopyrite. Chemical analysis of soil and stream sediment sampled over 1.5 km across at the Selogiri gold extraction site indicates that the site has been contaminated with mercury due to mining activities. The mercury concentrations in soil and stream sediments collected during dry season range from 0.01 to 481 ppm and 0.01 to 139 ppm, respectively, higher than background value of 0.05 ppm. In contrast, mercury concentration in stream sediments collected during rainy season from the same location as dry season sampling ranges from 0.01 to 13.42 ppm, and one sample has anomalous value of 331 ppm. This result show that rain water may disperse and decrease mercury concentration in stream sediments. In case of arsenic, although the ore contains rare arsenic minerals, arsenic concentration in bulk rock and ore is high ranging from 8 to 59 ppm, while the arsenic concentration in tailing is much higher ranging from 5.8 to 385 ppm. Chemical analyses on pyrite reveal that the pyrite grains contain arsenic and might be the source of arsenic in Selogiri mine site. However, analysis of dug-well water demonstrates that the mercury and arsenic content is still lower than the maximum allowable concentration. Keywords: Mercury, arsenic, contamination, Selogiri, gold mine

Floc size distribution and bacterial activities in membrane separation activated sludge processes for small-scale wastewater treatment/reclamation

1997 ◽  
Vol 35 (6) ◽  
pp. 37-44 ◽  
Author(s):  
Boran Zhang ◽  
Kazuo Yamamoto ◽  
Shinichiro Ohgaki ◽  
Naoyuki Kamiko
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Membrane Separation ◽  
Small Scale ◽  
Nitrification Rate ◽  
Floc Size ◽  
Denitrification Activity ◽  
Concentration Changes ◽  
Activated Sludge Processes

Activated sludges taken from full-scale membrane separation processes, building wastewater reuse system (400m3/d), and two nightsoil treatment plants (50m3/d) as well as laboratory scale membrane separation bioreactor (0.062m3/d) were analyzed to characterize membrane separation activated sludge processes (MSAS). They were also compared with conventional activated sludges(CAS) taken from municipal wastewater treatment plants. Specific nitrification activity in MSAS processes averaged at 2.28gNH4-N/kgMLSS.h were higher than that in CAS processes averaged at 0.96gNH4-N/kgMLSS.h. The denitrification activity in both processes were in the range of 0.62-3.2gNO3-N/kgMLSS.h without organic addition and in the range of 4.25-6.4gNO3-N/kgMLSS.h with organic addition. The organic removal activity in nightsoil treatment process averaged at 123gCOD/kgMLSS.h which was significantly higher than others. Floc size distributions were measured by particle sedimentation technique and image analysis technique. Flocs in MSAS processes changed their sizes with MLSS concentration changes and were concentrated at small sizes at low MLSS concentration, mostly less than 60 μm. On the contrary, floc sizes in CAS processes have not much changed with MLSS concentration changes and they were distributed in large range. In addition, the effects of floc size on specific nitrification rate, denitrification rate with and without organic carbon addition were investigated. Specific nitrification rate was decreased as floc size increased. However, little effect of floc size on denitrification activity was observed.

scholarly journals Evaluation of Fe-Mg Binary Oxide for As (III) Adsorption—Synthesis, Characterization and Kinetic Modelling

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 805
Author(s):  
Saif Ullah Khan ◽  
Rumman Zaidi ◽  
Feroz Shaik ◽  
Izharul Haq Farooqi ◽  
Ameer Azam ◽  
...  
Keyword(s):  
Arsenic Removal ◽  
Kinetic Modelling ◽  
Arsenic Concentration ◽  
Experimental Studies ◽  
Precipitation Method ◽  
Arsenic Adsorption ◽  
Adsorbent Dosage ◽  
X Ray ◽  
Co Precipitation ◽  
Contaminated Waters

Nanotechnology has received much attention in treating contaminated waters. In the present study, a facile co-precipitation method was employed to synthesize a novel iron and magnesium based binary metal oxide using a stoichiometrically fixed amount of FeNO3.9H2O and MgNO3.6H2O in a proportion of molar concentration 1:1 and was later evaluated in removing As (III) from contaminated waters. Characterization of the prepared nanomaterial was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX) and ultraviolet–visible spectrophotometry (UV-VIS). Experimental studies on batch scale were carried out, examining the effect of varying initial concentrations of metal, adsorbent dosage, application time and initial pH on removal efficiency. Arsenic removal increased on increasing adsorbent dosage (0.1–1 g/L) but trend reversed on increasing initial arsenic concentration attaining qmax of 263.20 mg/g. Adsorption was quite efficient in pH range 4–8. Freundlich fitted better for adsorption isotherm along with following Pseudo-2nd order kinetics. The reusability and effect of co-existing ions on arsenic adsorption, namely SO42−, CO32− and PO43− were also explored with reusability in 1st and 2nd cycles attained adsorptive removal up to 77% and 64% respectively. The prepared nano-adsorbent showed promising results in terms of high arsenic uptake (qmax of 263.20 mg/g) along with facile and cost-effective synthesis. Thus, the co-precipitation technique used in this work is a simple one step procedure without any use of any precursor as compared to most of the other procedures used for synthesis.

scholarly journals The Growth of Leaf Lettuce and Bacterial Communities in a Closed Aquaponics System with Catfish

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 222
Author(s):  
Kenji Yamane ◽  
Yuuki Kimura ◽  
Keita Takahashi ◽  
Isamu Maeda ◽  
Masayuki Iigo ◽  
...  
Keyword(s):  
Plant Growth ◽  
Early Stage ◽  
Amplicon Sequencing ◽  
Small Scale ◽  
Rrna Gene ◽  
Culture Solution ◽  
Beneficial Effects ◽  
Sustainable Cultivation ◽  
Microbial Groups ◽  
Production Period

Aquaponics is a circulating and sustainable system that combines aquaculture and hydroponics and forms a symbiotic relationship between fish, plants, and microorganisms. We hypothesized that feed alone could support plant growth, but the symbiosis with fish adds some beneficial effects on plant growth in aquaponics. In this study, we created three closed culture systems, namely, aquaponics, hydroponics without nitrogen (N) and phosphorus (P), and aquaculture, and added the same amount of feed containing N and P to all the treatments in order to test the hypothesis. Accumulation of NO3− and PO43− was alleviated in aquaponics and hydroponics as a result of plant uptake. Lettuce plants grown in aquaponics grew vigorously until 2 weeks and contained a constant level of N in plants throughout the production period, whereas those in hydroponics grew slowly in the early stage and then vigorously after 2 weeks with a late increment of N concentration. These results suggest that catfish help with the faster decomposition of the feed, but, in hydroponics, feed can be slowly dissolved and decomposed owing to the absence of the fish. The bacterial community structures of the culture solution were investigated using 16S rRNA gene amplicon sequencing. At the class level, Actinobacteria, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were the major microbial groups in the solutions. Aquaponics prevented the pollution of tank solution and maintained a higher water quality compared with hydroponics and aquaculture, suggesting that aquaponics is a more sustainable cultivation system even in a small-scale system.

scholarly journals The role of quantitative deep capillary plexus in the pathogenesis of type 3 macular neovascularization: an optical coherence tomography angiography study

2021 ◽  
Author(s):  
Marina Concilio ◽  
Federica Fossataro ◽  
Daniela Montorio ◽  
Mariapaola Giordano ◽  
Gilda Cennamo
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Early Stage ◽  
Study Groups ◽  
Control Group ◽  
Main Role ◽  
Optical Coherence ◽  
Capillary Plexus ◽  
Type 3

Abstract Purpose To quantitatively investigate the role of deep capillary plexus (DCP) in patients affected by type 3 macular neovascularization (MNV), compared to patients with reticular pseudodrusen (RPD) eyes and healthy controls, using optical coherence tomography angiography (OCTA). Methods In this prospective observational study, a total of seventy-eight eyes of 78 patients were included. Group 1 consisted of 40 eyes of 40 patients with stage 1 of type 3 MNV (22 males, 18 females, mean age 73.7, SD ± 6.60) and group 2 included 38 eyes of 38 patients with RPD (17 males, 21 females, mean age 73.2, SD ± 4.55). The control group included 40 eyes of 40 healthy subjects (20 males, 20 females, mean age 71.4, SD ± 6.36 years). We evaluated the retinal vessel density (VD) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) using OCTA. Results Patients with diagnosis of type 3 MNV showed statistically lower values of VD in DCP with respect to controls and to RPD group (p < 0.001), while there were no statistical differences between RPD and control group in macular region. No significant differences in VD of SCP were detected among the three study groups. Conclusion OCTA provides a reproducible, non-invasive detailed quantitative analysis of retinal vascular features and changing in early-stage type 3 MNV patients, which allowed to shed the light on the main role of DCP ischemia in the development of type 3 MNV.

scholarly journals Detonation effects of shallow buried explosive in sandy soil on target plate acceleration in a small-scale blast test

2018 ◽  
Vol 192 ◽  
pp. 02028
Author(s):  
Hassan Zulkifli Abu ◽  
Ibrahim Aniza ◽  
Mohamad Nor Norazman
Keyword(s):  
Sandy Soil ◽  
High Speed ◽  
Early Stage ◽  
Time History ◽  
Video Camera ◽  
Small Scale ◽  
Target Plate ◽  
Air Blast ◽  
High Speed Video Camera ◽  
The Impact

Small-scale blast tests were carried out to observe and measure the influence of sandy soil towards explosive blast intensity. The tests were to simulate blast impact imparted by anti-vehicular landmine to a lightweight armoured vehicle (LAV). Time of occurrence of the three phases of detonation phase in soil with respect to upward translation time of the test apparatus were recorded using high-speed video camera. At the same time the target plate acceleration was measured using shock accelerometer. It was observed that target plate deformation took place at early stage of the detonation phase before the apparatus moved vertically upwards. Previous data of acceleration-time history and velocity-time history from air blast detonation were compared. It was observed that effects of soil funnelling on blast wave together with the impact from soil ejecta may have contributed to higher blast intensity that characterized detonation in soil, where detonation in soil demonstrated higher plate velocity compared to what occurred in air blast detonation.

Kinetics, mass transfer, and mass re-equilibrium for arsenate adsorption on iron oxide-based carbons

2018 ◽  
Author(s):  
◽  
Zhengyang Wang
Keyword(s):  
Mass Transfer ◽  
Water Treatment ◽  
Large Scale ◽  
Freundlich Isotherm ◽  
Small Scale ◽  
Crossover Point ◽  
Hydraulic Residence Time ◽  
In Situ Extraction ◽  
Small Water ◽  
Batch Tests

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Removal of arsenic (As) from drinking water sources is much needed worldwide, and small water treatment systems, such as point-of-use (POU) treatment, could be an effective solution for residential applications. Adopting existing removal technologies that are successful in large-scale treatment to small-scale units, however, is rather ineffective due to the short hydraulic residence time in small water treatment systems. … The Freundlich isotherm can fit experimental data well: a crossover point for the two fitted Freundlich isotherms was observed and nano-FeAC had higher adsorption plateau. Furthermore, we demonstrated that due to the MRE process, a pseudo-equilibrium of FeMC was altered to another steady state by an in situ extraction with nano-FeAC in both batch and column systems. The overall inter-medium mass transfer resulted in both improved adsorption densities obtained by batch tests and a large bed volume prior to the 10 [mu]g As/L breakthrough at a short empty bed contact time (0.85 min).

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