removal capacity
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2022 ◽  
Vol 11 (2) ◽  
pp. 338
Author(s):  
Vicente Faus-Llácer ◽  
Dalia Pulido Ouardi ◽  
Ignacio Faus-Matoses ◽  
Celia Ruiz-Sánchez ◽  
Álvaro Zubizarreta-Macho ◽  
...  

The objective of the present study was to evaluate and compare the dentin removal capacity of Endogal Kids and Reciproc Blue NiTi alloy endodontic reciprocating systems for root canal treatments in primary second molar teeth via a micro-computed tomography (micro-CT) scan. Materials and Methods: Sixty root canal systems in fifteen primary second molar teeth were chosen and classified into one of the following study groups: A: EK3 Endogal Kids (n = 30) (EDG) and B. R25 Reciproc Blue (n = 30) (RB). Preoperative and postoperative micro-CT scans were uploaded into image processing software to analyze the changes in the volume of root canal dentin using a mathematical algorithm that enabled progressive differentiation between neighboring pixels after defining and segmenting the root canal systems in both micro-CT scans. Volumetric variations in the root canal system and the root canal third were calculated using a t-test for independent samples or a nonparametric Mann–Whitney–Wilcoxon test. Results: Statistically significant differences (p = 0.0066) in dentin removal capacity were found between the EDG (2.89 ± 1.26 mm3) and RB (1.22 ± 0.58 mm3) study groups for the coronal root canal third; however, no statistically significant differences were found for the middle (p = 0.4864) and apical (p = 0.6276) root canal thirds. Conclusions: Endogal and Reciproc Blue NiTi endodontic reciprocating systems showed similar capacity for the removal of root canal dentin, except for the coronal root canal third, in which the Reciproc Blue NiTi endodontic reciprocating system preserved more root canal dentin tissue.


Author(s):  
Li-Qiu Zhang ◽  
Xing Jiang ◽  
Hongwei Rong ◽  
Chun-Hai Wei ◽  
Min Luo ◽  
...  

As one stage process capable of simultaneous carbon and nitrogen removal, membrane aerated biofilm reactor (MABR) has advantages of low energy consumption from bubble-free aeration and no extra carbon dosage...


Author(s):  
Seemaa Ghate ◽  

Low light survivor house plants were assessed for their formaldehyde removal capacity from indoor environment. Low ventilation leading to poor air circulation in indoor environment has become a matter of grave concern as it leads to health issues. Phytoremediation technology is being studied in such situations. The capacity of plants in absorbing indoor pollutants can be enhanced through use of bacteria helping phytoremediation process. The gaseous formaldehyde of about 5 ppm was released into the static chamber of volume 1 m3 . Selected test plants were Aglaonema commutatum, Chlorophytum comosum, Sansevieria trifasciata and Epipremnum aureum. Medium in which plants were growing was inoculated with Pseudomonas chlororaphis, which helps the process of phytoremediation. Activated charcoal was also added in the medium, to increase the absorptive surface. The exposure given was for 24 hours. Experiment was replicated for three times. Air quality in the chamber was monitored on advanced Formaldehyde meter, at the start of the experiment and after 24 hours. Leaves of the plants were analysed by DNPH on LCMS method for quantification of Formaldehyde. Quantification of Formaldehyde from leaves ranged between 0.03–4.7 ppm. Formaldehyde meter showed reduction in formaldehyde quantity ranges from 1.999 to 0 ppm in 24 hours. This clearly indicates that selected plants have enhanced limited capacity of formaldehyde absorption in synergy with Pseudomonas chlororaphis.


Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 39
Author(s):  
Juanjuan Yang ◽  
Yu Song ◽  
Yan Yue ◽  
Wenfei Liu ◽  
Quande Che ◽  
...  

Here, a dual-modification strategy using KMnO4 (potassium permanganate) and AlCl3·6H2O (aluminum chloride, hexahydrate) as co-modifiers to improve the Cr(VI) removal capacity of K2CO3 activated biochar is introduced. As a result, the dual-modified biochar with KMnO4 and AlCl3·6H2O has the calculated adsorption energy of −0.52 eV and −1.64 eV for HCrO4−, and −0.21 eV and −2.01 eV for Cr2O72−. The Al2O3 (aluminum oxide) and MnO (manganese oxide) embedded on the surface of dual-modified biochar bring more Cr(VI) absorption sites comparing to single-modified biochar, resulting in a maximum Cr(VI) saturated adsorption capacity of 152.86 mg g−1. The excellent removal performance is due to the synthetic effect of electrostatic attraction, reduction reaction, complexation reaction, and physical adsorption. The experimental results also indicated that the spontaneous adsorption process agreed well with the pseudo-second order and Langmuir models. This dual-modification strategy is not limited to the treatment of Cr(VI) with biochar, and may also be incorporated with the treatment of other heavy metals in aqueous environment.


2021 ◽  
Vol 12 ◽  
Author(s):  
Sebastian Schaefer ◽  
Robin Steudtner ◽  
René Hübner ◽  
Evelyn Krawczyk-Bärsch ◽  
Mohamed L. Merroun

The remediation of heavy-metal-contaminated sites represents a serious environmental problem worldwide. Currently, cost- and time-intensive chemical treatments are usually performed. Bioremediation by heavy-metal-tolerant microorganisms is considered a more eco-friendly and comparatively cheap alternative. The fungus Penicillium simplicissimum KS1, isolated from the flooding water of a former uranium (U) mine in Germany, shows promising U bioremediation potential mainly through biomineralization. The adaption of P. simplicissimum KS1 to heavy-metal-contaminated sites is indicated by an increased U removal capacity of up to 550 mg U per g dry biomass, compared to the non-heavy-metal-exposed P. simplicissimum reference strain DSM 62867 (200 mg U per g dry biomass). In addition, the effect of temperature and cell viability of P. simplicissimum KS1 on U biomineralization was investigated. While viable cells at 30°C removed U mainly extracellularly via metabolism-dependent biomineralization, a decrease in temperature to 4°C or use of dead-autoclaved cells at 30°C revealed increased occurrence of passive biosorption and bioaccumulation, as confirmed by scanning transmission electron microscopy. The precipitated U species were assigned to uranyl phosphates with a structure similar to that of autunite, via cryo-time-resolved laser fluorescence spectroscopy. The major involvement of phosphates in U precipitation by P. simplicissimum KS1 was additionally supported by the observation of increased phosphatase activity for viable cells at 30°C. Furthermore, viable cells actively secreted small molecules, most likely phosphorylated amino acids, which interacted with U in the supernatant and were not detected in experiments with dead-autoclaved cells. Our study provides new insights into the influence of temperature and cell viability on U phosphate biomineralization by fungi, and furthermore highlight the potential use of P. simplicissimum KS1 particularly for U bioremediation purposes.Graphical Abstract


2021 ◽  
Author(s):  
Shehdeh Jodeh ◽  
Ahlam Jaber ◽  
Ghadir Hanbali ◽  
Younes Massad ◽  
Zaki S. Safi ◽  
...  

Abstract BackgroundHuman and veterinary antibiotics are typically discharged as parent chemicals in urine or feces and are known to be released into the environment via wastewater treatment plants (WWTPs). Several research investigations have recently been conducted on the removal and bioremediation of pharmaceutical and personal care products (PPCPs) disposed in wastewater. ResultsSiNP-Cu, a chelating matrix, was produced by delaying and slowing 1.5-dimethyl-1H-pyrazole-3-carbaldehyde on silica gel from functionalized with 3-aminopropyltrimethoxysilane. The prepared sorbent material was characterized using several techniques including BET surface area, FT-IR spectroscopy, Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and nitrogen adsorption-desorption isotherm. The pseudo-second-order model provided the best correlation due to the big match between the experimental and theoretical of different adsorption coefficients. The Langmuir and Freundlich adsorption models were used and the study showed better match with Fruendlich model. The removal capacity was depending on pH and increased by increasing pH The adsorbent demonstrated a high percentage removal of TMP, reaching more than 94 %. The sample was simply regenerated by soaking it for a few minutes in 1N HCl and drying it. The sorbent was repeated five times with no discernible decrease in removal capacity. Thermodynamic study also showed endothermic, increasing randomness and not spontaneous in nature. The findings of the DFT B3LYP/6-31+g (d,p) local reactivity descriptors revealed that nitrogen atoms and p-electrons of the benzene and pyrimidine rings in the TMP are responsible for the adsorption process with the SiNP surface. The negative values of the adsorption energies obtained by molecular dynamic simulation indicated the spontaneity of the adsorption process. ConclusionThe global reactivity indics prove that TMP is stable and it can be removed from wastewater using SiNP surface. The results of the local reactivity indices concluded that the active centers for the adsorption process are the nitrogen atoms and the p-electrons of the pyrimidine and benzene rings. Furthermore, the positive value of the maximum charge transfer number (DN) proves that TMP has a great tendency to donate electrons to SiNP surface during the process of adsorption.


Author(s):  
Samia Nasr ◽  
samira jeahi ◽  
Mustapha Hidouri ◽  
Khaled BOUGHZALA

Water is essential for all living things however its pain has become serious. Many industrial activities cause its pollution by the release of polluting byproduct. Waste water treatment is hence necessary. In this context, the waste water of the textile industry containing Red Acid 52 was treated by the solid waste of the washed natural phosphate byproduct. Natural phosphate was also studied. The solid materials were first characterized by chemical analysis, Fourier Transform Infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The phosphate materials were after that, tested in the adsorption of the Red Acid 52. The experimental data indicated that the phosphate waste rock allowed the removal of Red Acid 52. Its maximum retention capacity attained 18.4 mg.g-1. Calcinations of materials inhibits the removal capacity found reduced by 60 to 70%. The adsorption kinetics of the Red Acid 52 on the material is well described by the pseudo second order model while the adsorption isotherms are identified by the Langmuir model. Hereafter, the thermodynamic study revealed that the adsorption process is spontaneous and exothermic. Keywords: Waste water, Phosphate co-product, Adsorption, Red Acid 52.


Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3613
Author(s):  
Li Ji ◽  
Qili Ge ◽  
Yuan Li ◽  
Yifan Gao ◽  
Shulian Xie

Microalgae have shown great potential in wastewater treatment. This study evaluates the growth and nutrient removal characteristics of five different microalgae strains, namely Chlorella vulgaris, Tetradesmus obliquus, Parachlorella kessleri, Hydrodictyon sp., and Scenedesmus quadricauda, in simulated domestic wastewater. The five microalgae could adapt to wastewater, but the growth potential and nitrogen removal capacity were species dependent. The nutrient removal effect of the microalgae used in this experiment was about 50% in the first two days. Parachlorella kessleri, selected from the five strains of green algae, shows good potential in removing nutrients from simulated domestic wastewater. For the simulated domestic sewage treated with Parachlorella kessleri, the chemical oxygen demand was almost completely reduced, and ammonium-N (NH4-N) and total nitrogen (TN) removal exceeded 70% at the end of the 10-day treatment. Total phosphorus (TP) removal was slightly worse, more than 65%. Parachlorella kessleri showed the best growth in sewage with the highest biomass reaching 366.67 mg L−1 and the highest specific growth rate reaching 0.538 d−1. This study can provide a reference for selecting suitable microalgae species to treat actual domestic sewage.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7482
Author(s):  
Paweł Staroń ◽  
Jarosław Chwastowski

This study investigated the possibility of obtaining a raphia-microorganism composite for removing lead ions from aqueous solutions using immobilized yeast cells Saccharomyces cerevisiae on Raphia farinifera fibers. The obtained biocomposite was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. Studies were conducted to determine the influence of contact time, initial concentration of Pb(II), and pH allowed for the selection of nonlinear equilibrium and kinetic models. The results showed that the biocomposite had a better Pb(II) removal capacity in comparison to the raphia fibers alone, and its maximum Pb(II) adsorption capacity was 94.8 mg/g. The model that best describes Pb(II) sorption was the Temkin isotherm model, while kinetic studies confirmed the chemical nature of the sorption process following the Elovich model. The obtained research results provide new information on the full use of the adsorption function of biomass and the ubiquitous microbial resources and their use in the remediation of aqueous environments contaminated with heavy metals.


2021 ◽  
Author(s):  
Hong Yang ◽  
Xiaotong Wang

In view of the problems of slow start, easy loss and sensitive to low temperature environment in the suspension culture of anaerobic ammonia oxidation bacteria (AnAOB) suspension culture, polyvinyl alcohol (PVA) was used to prepare the anaerobic ammonia oxidation (anammox) immobilized filler, so as to realize the rapid start-up and activity improvement of anammox. Meanwhile, the response of nitrogen removal performance of encapsulated biomass to temperature reduction was determine by batch experiment. In addition, changes in the internal structure, flora composition and diversity of the filler were analyzed by scanning electron microscopy (SEM) and high-throughput sequencing. The results showed that the nitrogen removal capacity of the immobilized filler (E1) was significantly higher than that of the suspended sludge contrast system (S1) after 100d enrichment culture. The final nitrogen removal rate reached 1.168kg·(m3·d-1) -1, and the total nitrogen removal efficiency was 92%. The immobilization improved the resistance of AnAOB to low temperature. At 15°C, the effluent ammonia and nitrite of S1 were seriously accumulated, and E1 could maintain a stable nitrogen removal effect under the regulation of HRT. The population diversity was maintained in the immobilized filler, and the functional bacteria of anammox Candidatus Kuenenia was effectively enriched, accounting for 32.55% in E1. The results of this study provide valuable information for the application and popularization of anammox immobilized filler.


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