scholarly journals An Innovative Digestion Method: Ultrasound-Assisted Electrochemical Oxidation for the Onsite Extraction of Heavy Metal Elements in Dairy Farm Slurry

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4562
Author(s):  
Chenyu Li ◽  
Bin Xue ◽  
Shang Wang ◽  
Xi Zhang ◽  
Chen Zhao ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Particle Size ◽  
Electrochemical Oxidation ◽  
Dairy Farm ◽  
Operating Parameters ◽  
Digestion Time ◽  
Digestion Method ◽  
Ultrasound Assisted ◽  
Digestion Efficiency ◽  
Cu And Zn

Dairy farm slurry is an important biomass resource that can be used as a fertilizer and in energy utilization and chemical production. This study aimed to establish an innovative ultrasound-assisted electrochemical oxidation (UAEO) digestion method for the rapid and onsite analysis of the heavy metal (HM) contamination level of dairy slurry. The effects of UAEO operating parameters on digestion efficiency were tested based on Cu and Zn concentrations in a dairy slurry sample. The results showed that Cu and Zn digestion efficiency was (96.8 ± 2.6) and (98.5 ± 2.9)%, respectively, with the optimal UAEO operating parameters (digestion time: 45 min; ultrasonic power: 400 W; NaCl concentration: 10 g/L). The digestion recovery rate experiments were then operated with spiked samples to verify the digestion effect on broad-spectrum HMs. When the digestion time reached 45 min, all digestion recovery rates exceeded 90%. Meanwhile, free chlorine concentration, particle size distribution, and micromorphology were investigated to demonstrate the digestion mechanism. It was found that 414 mg/L free chorine had theoretically enough oxidative ability, and the ultrasound intervention could deal with the blocky undissolved particles attributed to its crushing capacity. The results of particle size distribution showed that the total volume and bulky particle proportion had an obvious decline. The micromorphology demonstrated that the ultrasound intervention fragmented the bulky particles, and electrochemical oxidation made irregular blocky structures form arc edge and cellular structures. The aforementioned results indicated that UAEO was a novel and efficient method. It was fast and convenient. Additionally, it ensured digestion efficiency and thus had a good application prospect.

scholarly journals Development of Optimal Digesting Conditions for Microplastic Analysis in Dried Seaweed Gracilaria fisheri

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2118
Author(s):  
Rizky Prihandari ◽  
Weeraya Karnpanit ◽  
Suwapat Kittibunchakul ◽  
Varongsiri Kemsawasd
Keyword(s):  
Raman Spectroscopy ◽  
Recovery Rate ◽  
Combination Method ◽  
High Polymer ◽  
Digestion Time ◽  
Digestion Method ◽  
Marine Food Web ◽  
Marine Food ◽  
Digestion Efficiency ◽  
Digestion Methods

Currently, research on the accumulation of microplastics (MPs) in the marine food web is being highlighted. An accurate and reliable digestion method to extract and isolate MPs from complex food matrices has seldom been validated. This study aimed to compare the efficacy of MP isolation among enzymatic-, oxidative-, and the combination of two digestion methods on red seaweed, Gracilaria fisheri. The dried seaweed sample was digested using three different methods under various conditions using enzymes (cellulase and protease), 30% H2O2, and a combination of enzymes and 30% H2O2. The method possessing the best digestion efficiency and polymer recovery rate of MPs was selected, and its effect on spiked plastic polymer integrity was analyzed by Raman spectroscopy. As a result, the enzymatic method rendered moderate digestion efficiency (59.3–63.7%) and high polymer recovery rate (94.7–98.9%). The oxidative method using 30% H2O2 showed high digestion efficiency (93.0–96.3%) and high polymer recovery rate (>98%). The combination method was the most effective method in terms of digestion efficiency, polymer recovery rate, and expenditure of digestion time. The method also showed no chemical changes in the spiked plastic polymers (PE, PP, PS, PVC, and PET) after the digestion process. All the spiked plastic polymers were identifiable using Raman spectroscopy.

scholarly journals Novel AOPs-Based Dual-Environmental Digestion Method for Determination of Total Dissolved Nitrogen in Water

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2751
Author(s):  
Rongyao Cai ◽  
Weiqiang Shou ◽  
Xiaochun Hu ◽  
Luyue Xia ◽  
Mengfei Zhou ◽  
...  
Keyword(s):  
Online Monitoring ◽  
Digestion Time ◽  
Digestion Method ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Digestion Efficiency ◽  
N Compounds

Based on a synergistic digestion method of ultraviolet combined with ozone (UV/O3), this article investigates the reaction characteristics of nitrogen-containing compounds (N-compounds) in water and the influence of ions on digestion efficiency. In this respect, a novel and efficient AOPs-based dual-environmental digestion method for the determination of total dissolved nitrogen (TDN) in waters with complex components is proposed, in the hopes of improving the detection efficiency and accuracy of total nitrogen via online monitoring. The results show that inorganic and organic N-compounds have higher conversion rates in alkaline and acidic conditions, respectively. Meanwhile, the experimental results on the influence of Cl−, CO32−, and HCO3− on the digestion process indicate that Cl− can convert to radical reactive halogen species (RHS) in order to promote digestion efficiency, but CO32− and HCO3− cause a cyclic reaction consuming numerous •OH, weakening the digestion efficiency. Ultimately, to verify the effectiveness of this novel digestion method, total dissolved nitrogen samples containing ammonium chloride, urea, and glycine in different proportions were digested under the optimal conditions: flow rate, 0.6 L/min; reaction temperature, 40 °C; pH in acidic conditions, 2; digestion time in acidic condition, 10 min; pH in alkaline conditions, 11; digestion time in alkaline conditions, 10 min. The conversion rate (CR) of samples varied from 93.23% to 98.64%; the mean CR was greater than 95.30%. This novel and efficient digestion method represents a potential alternative for the digestion of N-compounds in the routine analysis or online monitoring of water quality.

Comparison of Digestion Methods for Analysis of Heavy Metals in MSWI Bottom Ash

2011 ◽  
Vol 474-476 ◽  
pp. 1075-1080 ◽  
Author(s):  
Hai Ying Zhang ◽  
Yi Zheng ◽  
Hong Tao Hu ◽  
Jing Yu Qi
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Content ◽  
Bottom Ash ◽  
Waste Incineration ◽  
Municipal Solid Waste Incineration ◽  
Digestion Method ◽  
Mswi Bottom Ash ◽  
Digestion Efficiency ◽  
Digestion Methods

This work aims to develop a proper digestion method for measurement of heavy metal content in municipal solid waste incineration (MSWI) bottom. Different digestion methods by HNO3, HNO3/HCl, HNO3/HCl/HClO4, HNO3/HCl/H2O2, HNO3/HClO4, HNO3/H2O2, were compared in digestion efficiency, and Cu, Pb, Zn and Cd were analyzed using atomic absorption spectrum (AAS). The method using mixed HNO3/HCl/HClO4 was recommended for digestion of MSWI slag for measurement of Cu, Pb, Zn, and the method of HNO3/H2O2 recommended for digestion for measurement of Cd.

HEAVY METALS IN WATER, SEDIMENTS AND MARINE FISHES FROM BULGARIAN BLACK SEA

2017 ◽  
Author(s):  
Katya Peycheva ◽  
Katya Peycheva ◽  
Mona Stancheva ◽  
Mona Stancheva ◽  
Stanislava Georgieva ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Black Sea ◽  
Fish Species ◽  
Distribution Patterns ◽  
Marine Fishes ◽  
Marine Water ◽  
Mean Values ◽  
Sprattus Sprattus ◽  
Cu And Zn

In this study, the ecosystem marine water-sediment-biota was investigated and the pollution was assessed. The concentrations of eight elements were determined in marine water, sediments and four fish species collected from Black Sea (Varna), Bulgaria during 2013. Marine water recorded the highest concentrations of Zn (15-22 μg/L), As (1.1–1.2 μg/L) and Pb (0.7-0.8 μg/L) while Zn (31-52 μg/g), Pb (21-29 μg/g) and Cu (20-34 μg/g) and show the highest concentrations in sediments. Water and sediments showed similar spatial distribution patterns for the highest mean values of the different metals. In the analysed fish species, the highest concentration of the metals Cu and Zn were found in Trachurus Mediterrneus (0.42 mg/kg w.w) and in Sprattus Sprattus (12.7 mg/kg w.w), respectively while the heavy metals As and Hg were found with maximum values in Pseta Maxima (3.99 mg/kg w.w and 0.08 mg/kg w.w respectively). The results from this study were compared with our data for a previous period (2004-2006) and they show decrease in the levels of heavy metal.

Metallic pollution in clogging materials of urban porous pavements

1995 ◽  
Vol 32 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Valérie Colandini ◽  
Michel Legret ◽  
Yves Brosseaud ◽  
Jean-Daniel Baladès
Keyword(s):  
Heavy Metal ◽  
Particle Size ◽  
Road Traffic ◽  
Total Concentration ◽  
Extraction Procedure ◽  
Interaction Strength ◽  
Metal Mobility ◽  
Residual Fraction ◽  
Metal Contents ◽  
Copper Zinc

Porous pavements infiltrated with stormwater are faced with clogging problems: runoff particles seep and clog the pervious surface layer of these structures. Clogging material samples (in the form of sludge) have been collected in cleaning operations on the pervious asphalt. This study aims at characterizing these materials, particle size distribution, heavy metal contents by particle size, and studying interactions between metals and particles. A sequential extraction procedure proposed by the experts of the Community Bureau of Reference (B.C.R.) was applied to provide information about heavy metal distribution on particles and to evaluate interaction strength, and consequently potential metal mobility when chemical variations occurred in the environment. Mainly made up of sand, the materials are polluted with lead, copper, zinc and cadmium. The concentrations appeared to be linked with road traffic intensity. The heavy metal contents by particle size showed that the finer are the particles, the higher are the heavy metal concentrations. Heavy metals were found potentially labile; metals contents in the residual fraction (mineral fraction) represented less than 20 % of the total concentration. Cadmium and zinc were apparently more labile than lead and copper.

Ultrasound-Assisted Citric Acid Extraction of Zinc in Plateau Red Soil and Tessier Speciation Study

2013 ◽  
Vol 726-731 ◽  
pp. 4464-4467
Author(s):  
Wei Wei ◽  
Xue Jin Zhou ◽  
Yun Tao Gao
Keyword(s):  
Heavy Metal ◽  
Citric Acid ◽  
Manganese Oxides ◽  
Red Soil ◽  
Extraction Rate ◽  
Acid Extraction ◽  
Speciation Study ◽  
Ultrasonic Assisted ◽  
Ultrasound Assisted ◽  
Iron And Manganese

Taking plateau red soil as research object, using the ultrasonic-assisted organic acid extraction the heavy metal zinc in it, and analyze the form of zinc. Results showed that the extraction rate can reach 68%, with the increase of time, the extraction effect of zinc is obviously enhanced in this method. Ultrasonic-assisted citric acid extraction soil can increase the extraction rate of exchangeable, bound to carbonates and bound to iron and manganese oxides relatively.

Spatial and Temporal Distribution of Heavy Metals Concentration in Urban Stormwater Runoff

2013 ◽  
Vol 726-731 ◽  
pp. 1801-1804 ◽  
Author(s):  
Shu Min Wang ◽  
Hui Yu
Keyword(s):  
Heavy Metal ◽  
Stormwater Runoff ◽  
Temporal Distribution ◽  
Urban Region ◽  
Spatial And Temporal Distribution ◽  
Urban Stormwater ◽  
Metal Concentrations ◽  
Heavy Metal Concentrations ◽  
Urban Stormwater Runoff ◽  
Cu And Zn

In order to know the characteristic of spatial and temporal distribution of heavy metal concentrations in urban stormwater runoff, rainfall runoff from impervious underlying surfaces in urban region was observed during rain events. Results showed that during the precipitation process, heavy metal concentrations decreased gradually temporally (except Cd); concentrations of Fe, Cu and Zn meet Class III standard of Environmental Quality Standards for Surface Water in terminal runoff, but concentrations of Cd and Pb go beyond this standard far. Heavy metal concentrations in runoff from different types of landuses were significantly different. The arithmetic average concentrations of Fe, Cd, Cu and Zn in stormwater runoff from roof (e.g.,34.4mg/L, 0.15mg/L, 1.25mg/L and 1.23mg/L, respectively) were obviously higher than that in stormwater runoff from road (e.g., 11.8mg/L, 0.05mg/L, 0.13mg/L and 0.69mg/L, respectively).

Influence of speciation distribution and particle size on heavy metal leaching from MSWI fly ash

2022 ◽  
Vol 138 ◽  
pp. 318-327
Author(s):  
Davide Bernasconi ◽  
Caterina Caviglia ◽  
Enrico Destefanis ◽  
Angelo Agostino ◽  
Renato Boero ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Particle Size ◽  
Fly Ash ◽  
Metal Leaching ◽  
Mswi Fly Ash ◽  
Heavy Metal Leaching
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