Environmental Technology

Poorasadollah, Delaram; Bagheri Lotfabad, Tayebe; Heydarinasab, Amir; Yaghmaei, Soheila; Mohseni, Farzaneh Aziz

doi: 10.1080/09593330.2021.1897167pmid: 33641622

The feasibility of employing the biological activated carbon (BAC) process to debilitate azo dye Carmoisine by Klebsiella spp. was investigated. Plate assay revealed the capability of Klebsiella spp. for removal of Carmoisine via degradation. Kinetic parameters were measured for Carmoisine debilitation by Klebsiella spp. using the suspended anaerobic process. Two types of granular and rod-shaped activated carbon were used to form the biological beds in order to study the Carmoisine debilitation in batch processes. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to indicate the colonization and biofilm formation of bacteria grown on activated carbon particles (ACPs). Thin-layer chromatography (TLC), liquid chromatography–mass spectrometry (LC–MS), high-pressure liquid chromatography (HPLC) and biosorption studies demonstrated biotransformation of Carmoisine into its constituent aromatic amines during the Carmoisine debilitation in suspended anaerobic and BAC processes. The porosity of activated carbons, inoculation size and age of biological beds were the important factors affecting the viability of bacterial cells grown on ACPs and, consequently, the rate and efficiency of the Carmoisine debilitation process determined through spectrophotometry. The reusability of biological beds was demonstrated by conducting sequential batch experiments. In conclusion, the BAC process proved to be an efficient method for anaerobic dye degradation.

Yang, Ting; Hao, Qian; Qiao, Yajie; Fu, Zhimin

doi: 10.1080/09593330.2021.1899291pmid: 33683170

The effect of low strength on anaerobic ammonium oxidation (anammox) was investigated in an anaerobic moving bed biofilm reactor (AMBBR) treating artificial wastewater. Influent -N concentration with 10.74 ± 2.73 mg L−1 adversely impacted nitrogen removal permanence, the total nitrogen removal efficiency was significantly increased from 61.4% to 80.0%, when influent nitrogen increased to 22.36 ± 5.83 mg·L−1. -N removal efficiency decreased obviously while that of -N was basically unaffected by the influent nitrogen concentration decrease. Illumina high-throughput sequencing results revealed that the predominant bacterial (64.71%) phylum was Proteobacteria and the dominant functional microorganisms were Nitrosospira, Nitrospira, and Candidatus Brocadia. Simple model simulation results showed that the inhibition effect of the low substrate was most likely due to the increase of bulk DO, which comes from influent and gas–liquid transfer. The reversible inhibition effect of low strength on nitrogen removal performance in an anammox reactor was demonstrated, and strictly regulation of the bulk DO was presumed to be critical to achieve a successful and stable operating performance under low strength.

Xie, Linxuan; Lu, Jun; Ye, Ganggui; Yao, Jieyu; Zou, Xuehua; Zhu, Chengzhu

doi: 10.1080/09593330.2021.1899292pmid: 33657965

Copper oxide and hematite (CuO/α-Fe2O3) composite catalysts were prepared by using goethite as precursor adopted impregnation way and applied to the dielectric barrier discharge (DBD) catalytic decomposition of gaseous chlorobenzene. The CuO/α-Fe2O3 composite was characterised by X-ray diffraction, Brunauer–Emmett–Teller method, scanning electron microscopy and X-ray photoelectron spectrometer technique. The decomposition efficiency and energy yield of gaseous chlorobenzene in DBD catalysis system were studied by a function of gas flow rate, initial concentration and input voltage. The results showed that the CuO/α-Fe2O3 composite catalyst exhibited remarkable performance on chlorobenzene decomposition when the molar ratio was 0.4 and calcination temperature was 450°C. When the chlorobenzene initial concentration was 230 mg m−3, the chlorobenzene decomposition efficiency and mineralisation rate on the DBD catalysis system reached 73.33% and 63.37%, respectively, its decomposition and mineralisation efficiency were enhanced about 20.5% and 16.61%, respectively, compared with the bare DBD system, and it also benefited to significantly reduce the ozone and NO2 by-products. The possible pathway of chlorobenzene decomposition in the DBD catalytic hybrid system was proposed based on the products analysis.

Eimontas, Justas; Striūgas, Nerijus; Zakarauskas, Kęstutis; Navickas, Kęstutis; Venslauskas, Kęstutis

doi: 10.1080/09593330.2021.1901148pmid: 33678146

Marine biomass is a promising renewable energy source, especially as this waste contains a large amount of cellulose and hemicellulose, which can contribute to convert it into energy products using anaerobic digestion (AD) and pyrolysis processes. This work was focused on a synergetic view of marine coastal waste treatment (seaweed) using two different technologies, anaerobic microbiological co-digestion, and pyrolysis. The experiments were performed with two merged technologies to assess the captured energy from the digestate in case it is contaminated. Anaerobic co-digestion was conducted using a periodic load laboratory bench with a vertical biogas digester. An evaluation of possible product yields and composition during pyrolysis at a laboratory-scale bench has been performed. The products obtained after the thermal treatment analyzed using an online gas measurement system and gas chromatographs Agilent 7890A with TCD detector (for gases) and Agilent 7890A with MS detector (for liquids). The results demonstrated that biogas yield was 174.1 l/kg (DM). Seaweed washed by seawater yields a higher amount of biogas (202.5 l/kg). Meanwhile, seaweed, sewage sludge, and digestate samples subjected to thermal treatment produced 17%, 30%, and 15% of liquids products, respectively. The economic performance assessment showed that the application of the developed merged approach on an industrial scale could provide an economic return of up to 8.3 $/100 kg of waste. Based on that, merged AD and pyrolysis technologies could be adapted as a promising technology to valorize seaweed wastes and utilize them as a new sustainable source for renewable energy.

Yan, Ling; Gu, Weishi; Zhou, Nan; Ye, Changqing; Yang, Yuhuan

doi: 10.1080/09593330.2021.1903563pmid: 33719868

In this work, a novel adsorbent of aluminium/lanthanum loaded wheat straw biochar (Al-La-WSB), was prepared by using a facile approach and used for fluoride removal. The Al-La-WSB and its pristine wheat straw biochar (WSB) were characterized by scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray powder diffraction (XRD) methods. Batch adsorption experiments were carried out to investigate adsorbent performance, the highest removal rate was observed at pH 9, contact time of 7 h and Al-La-WSB dose of 1 g L−1. Lagergren pseudo-second-order kinetics and Langmuir isotherm model fitted the experimental data well. The maximum fluoride adsorption capacity of Al-La-WSB at different experiment temperature of 298, 308 and 318 K, was 51.28 mg g–1, 46.73 mg g–1 and 50.25 mg g–1, respectively, which was better than most reported adsorbents. The Al-La-WSB performed well over a considerable wide pH range of 3–10 and carried positive charge at pH < 4.8. The presence co-existing ions of SO4 2−, HCO3 −, Cl− and NO3 − had a minor impact on fluoride adsorption besides PO4 3−. Regeneration experiment results showed that the Al-La-WSB had an excellent reusability. According to the adsorbent characterization and batch adsorption experiment, the adsorption of fluoride on the Al-La-WSB was primarily a chemisorption, involving electrostatic interactions and ion exchange, which nitrate ion and hydroxyl played a major role. The results suggested that the Al-La-WSB could be a great adsorbent for removing fluoride from drinking water.

Liu, Jiyang; Yu, Haojie; Wang, Li

doi: 10.1080/09593330.2021.1903564pmid: 33739227

The treatment of wastewater containing organic pollutants has become a serious issue, and one of the advanced oxidation process, Fenton oxidation is recognized as an ideal way owing to its universality and environmental friendliness, thus efficient and economic catalysts are in great demand. Herein by incorporating Fe2+ containing compound as ligand, a tremella-like iron containing metal–organic framework (TFMOF) was synthesized with zirconium acetate and 1,1′-ferrocene-dicarboxylic acid though a facile solvothermal method. The TFMOF combined the merits of both ferrocene moiety with well dispersed Fe2+ sites in the molecular level and MOF films with large surface areas and exposed sites. And the morphology and crystal structure of TFMOF were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Moreover, employed as an effective catalyst in Fenton oxidation, over 99%, 95% and 97% of rhodamine B, methyl orange and reactive black V were rapidly degraded without the assistance of additional irradiation, and degradation conditions like pH, H2O2 and initial pollutant concentrations as well as the reaction kinetic was investigated, indicating the hydroxyl radical generated in the presence of TFMOF and H2O2 was able to degrade the pollutants into non-toxic molecular. Besides, the catalytic activity of TFMOF maintained well after three cycles. The good activity and universality of TFMOF make it a promising catalyst for the treatment of wastewater.

Chen, Mingxing; Guo, Qinming; Cui, Jinping; Lv, Weiyang; Yao, Yuyuan

doi: 10.1080/09593330.2021.1903566pmid: 33719927

Developing high-performance adsorbent for hexavalent chromium (Cr(VI)) elimination presents an enticing prospect in environmental remediation. Herein, three-dimensional flowerlike nanospheres composed of molybdenum disulphide and polypyrrole (MoS2@PPy) were successfully prepared via a one-pot hydrothermal and subsequent carbothermal reduction process for the removal of Cr(VI). The effects of pH, adsorbent dosage, co-existing ions, initial Cr(VI) concentration and temperature were investigated systematically by batch experiments. Benefiting from the incorporation of MoS2, the obtained MoS2@PPy composites showed a dramatic increase of specific surface area (149.82 m2·g−1) and adsorption capacity (230.97 mg·g−1) when compared with the pure PPy nanoparticles. Based on the thermodynamics study and X-ray photoelectron spectroscopy analyses, the removal process of Cr(VI) was proved to be exothermic and spontaneous, and accessible under-coordinated Mo(IV) and pyrrolic N groups coupled with redox reactions were conducive to the efficient removal of Cr(VI). Attractively, the MoS2@PPy acted as the electron donor could also activate peroxymonosulphate for the efficient degradation of organic contaminants. These results suggested that the MoS2@PPy was promising in Cr(VI) elimination and other kinds of organic pollutants removal in wastewater.

Kuşçu, Özlem Selçuk; Çömlekçi, Selçuk; Çört, Nihal

doi: 10.1080/09593330.2021.1906324pmid: 33754952

A Pulsed Electrical Field (PEF) reactor was developed to process biological sludge as a pretreatment method prior to anaerobic digestion. This study focuses on the effects of operational parameters such as applied voltage, pH, conductivity, flow-rate, and temperature affecting the treatment of waste active sludge (WAS) by PEF, the simulation of reactor process conditions and anaerobic biodegradation of PEF pretreated sludge. The effects of the sludge conductivity, flow-rate, and temperature on the Soluble Chemical Oxygen Demand (SCOD) of WAS treated by PEF reactor were investigated by using a Box–Wilson statistical experiment design. Simulations of the PEF process conditions were performed to verify experimental results. After PEF optimization study, the PEF operational conditions for maximum SCOD were obtained at 4 mS/cm conductivity, 5 mL/min flow-rate, and 40 °C temperature during PEF treatment. The measured and predicted SCOD showed a good consistency (R 2 = 0.92). After it was pretreated by the PEF, the SCOD, total nitrogen, total phosphorus, polysaccharide and protein contents of WAS increased. However filterability property also decreased. In the anaerobic digestion study, the reactor fed with the PEF pretreated WAS provided 1.70 times higher methane production compared with raw sludge. In addition to this situation, 18% and 19% improvements, respectively, were observed in SCOD and VSS reductions when it was compared with raw sludge in the 23 days of anaerobic operation. Sixteen percent decrease in CST showed that the PEF enhanced the filterability of WAS during the anaerobic stabilization.

Anjos, Raoni Batista dos; Silva, Wanessa Paulino Neves; Silva, Aldo Aloísio Dantas da; Barros, Sergio Ricardo da Silveira; Carvalho Filho, Edvaldo Vasconcelos de

doi: 10.1080/09593330.2021.1906325pmid: 33739237

Cases of oil spillage and leakage in marine environments are increasing, and generating a need to quickly assess the presence of these contaminants in seawater. This work aims to estimate the concentrations of benzene, toluene, ethylbenzene and xylenes (BTEX) dissolved in seawater in cases of oil spillage using experimental factorial planning. The study factors were oil °API and oil/seawater contact time after spillage. The models obtained were able to satisfactorily estimate BTEX concentrations, with accuracy greater than 99.3% within the ranges studied, with R² correlation coefficients ranging from 0.992 to 0.997. The models presented forecast efficiency higher than 88%, with low relative errors, ranging from 0.1% to 12%. The concentrations of benzene dissolved in seawater found experimentally with only one hour of spillage, for the two types of oils studied, were higher than allowed by Brazilian legislation, demonstrating real environmental risk in cases of spillage of these types of oil into the sea. These results can corroborate the development of a risk assessment in oil spills within the studied ranges and serve as a useful analytical tool for emergencies.

Ma, Jie; Ding, Yi; Gu, Chunyun; Zhai, Guangyao; Liu, Yanbo; Wen, Jing; Rong, Xun; Luo, Chaoyi; Qiu, Ye; Zhang, Ping

doi: 10.1080/09593330.2021.1906326pmid: 33739234

Benzothiazole (BTH) is an aromatic heterocyclic compound with wide industrial applications. In view of its toxicity and wide environmental presence, previous efforts have been made to decompose BTH via different degradation pathways. However, due to its recalcitrant nature, conventional biological treatment methods cannot completely degrade BTH in the wastewater. In this study, sulfate radical-based advanced oxidation process (AOP) technique has been adopted to degrade BTH in aqueous phase. Persulfate (PS) was employed as radical promotor to generate sulfate radical via heat activation. Degradation of BTH by thermally activated persulfate via AOP has been experimentally evaluated in a systematic manner. Laboratory efforts have been made to examine the impact of a number of physiochemical parameters including the type of oxidants, reaction temperature, initial concentrations of PS and BTH, solution pH, and the presence of anionic species. It shows that a higher BTH degradation rate can be achieved by lowering BTH initial concentration or increasing PS concentration. Increasing solution pH or the presence of 10 mM of Cl−, Br−, , or species can decrease BTH degradation rate. Furthermore, the primary radical(s) responsible for BTH degradation have been identified as sulfate radical at an acidic aqueous condition, and hydroxyl radical and sulfate radical combined at a basic condition. This study provides the necessary theoretical and technical foundations for BTH degradation via sulfate radical-based AOP technique. The conclusions from this study can substantially promote the field application of AOP, especially sulfate radical-based AOP technique, for BTH degradation in wastewater treatment process.