scholarly journals Parametric optimization of cyanobacterial coagulation at exponential and decline phases by combining polyaluminum chloride and cationic polyacrylamide

2021 ◽  
Author(s):  
Weijun Song ◽  
Yu Xie ◽  
Xi Li
Keyword(s):  
Chlorophyll A ◽  
Parametric Optimization ◽  
Ph Value ◽  
Cyanobacterial Bloom ◽  
Influence Factors ◽  
Exponential Phase ◽  
Polyaluminum Chloride ◽  
Cationic Polyacrylamide ◽  
Removal Ratio ◽  
Decline Phase

Abstract Microcystis spp. is the most common and problematic species during cyanobacterial bloom. This study employed Microcystis aeruginosa for coagulation experiments. Effects of polyaluminum chloride (PAC), cationic polyacrylamide (CPAM), and pH value on cyanobacterial removal at exponential and decline phases by coagulation were investigated by measuring chlorophyll a. A mathematical model between factors and response variables was established using response surface methodology (RSM). Results showed that factors of CPAM dosage, PAC dosage, and pH value could strongly affect the removal ratio of Microcystis at both exponential and decline phases. RSM revealed that the order of influence factors on the removal of chlorophyll a was CPAM > PAC > pH for Microcystis at the exponential phase, and these orders of CPAM > PAC > pH (PAC coagulation) and CPAM > PAC > pH (CPAM coagulation) were for Microcystis at the decline phase. It suggested that the growth phase of cyanobacteria was also quite important to optimize the coagulation process. Besides, a fitted model was developed, and it could well predict the removal ratio of chlorophyll a by coagulation with various treatments. The model recommended dosages of CPAM (3.72 mg/L) and PAC (10.23 mg/L) for Microcystis at the exponential phase with a pH value of 8.25, and dosages of CPAM (5.98 mg/L) and PAC (17.81 mg/L) were for Microcystis at the decline phase with a pH value of 8.21. Overall, these results would provide a technical guideline of combining PAC and CPAM to treat cyanobacteria at exponential and decline phases.

scholarly journals Study on Chromaticity Removal from Mineral Processing Wastewater with Salicylic Hydroxamic Acid by Granular Activated Carbon Catalyzed Ozonation

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 359
Author(s):  
Liping Zhang ◽  
Shengnian Wu ◽  
Nan Zhang ◽  
Ruihan Yao ◽  
Eryong Wu
Keyword(s):  
Activated Carbon ◽  
Reaction Time ◽  
Hydroxamic Acid ◽  
Ph Value ◽  
Oxygen Demand ◽  
Granular Activated Carbon ◽  
Mineral Processing ◽  
Ultraviolet Absorption Spectrum ◽  
Experimental Conditions ◽  
Removal Ratio

Salicylic hydroxamic acid is a novel flotation reagent used in mineral processing. However, it impacts the flotation wastewater leaving behind high chromaticity which limits its reuse and affects discharge for mining enterprises. This study researched ozonation catalyzed by the granular activated carbon (GAC) method to treat the chromaticity of the simulated mineral processing wastewater with salicylic hydroxamic acid. The effects of pH value, ozone (O3) concentration, GAC dosage, and reaction time on chromaticity and chemical oxygen demand (CODCr) removal were discussed. The results of individual ozonation experiments showed that the chromaticity removal ratio reached 79% and the effluent chromaticity exceeded the requirement of reuse and discharge when the optimal experimental conditions were pH value 3, ozone concentration 6 mg/L, and reaction time 40 min. The orthogonal experimental results of catalytic ozonation with GAC on chromaticity removal explained that the chromaticity removal ratio could reach 96.36% and the chromaticity of effluent was only 20 when the optimal level of experimental parameters was pH value 2.87, O3 concentration 6 mg/L, GAC dosage 0.06 g/L, reaction time 60 min respectively. The degradation pathway of salicylic hydroxamic acid by ozonation was also considered based on an analysis with ultraviolet absorption spectrum and high-performance liquid chromatography (HPLC).

scholarly journals Extraction of tetracycline using the ionic liquid-based aqueous two phase systems: Single-stage versus multi-stage

2018 ◽  
Vol 24 (4) ◽  
pp. 387-397 ◽  
Author(s):  
Yi Liu ◽  
Li Chen ◽  
Jun Zhou ◽  
Zongcheng Yan
Keyword(s):  
Extraction Efficiency ◽  
Ph Value ◽  
Influence Factors ◽  
Volume Ratio ◽  
Line Length ◽  
Single Stage ◽  
Two Phase ◽  
Extraction Behavior ◽  
Multi Stage ◽  
Tie Line

Ionic liquids-based aqueous two-phase extraction (ILs-ATPE) offers an alternative approach to the extraction of tetracycline (TC) through their partitioning between two phases. Single-stage and multi-stage strategies have been evaluated and compared for the purification of TC using ATPE composed of 1-butyl-3-methylimidazolium halide ([Bmim]X(X=Cl,Br)) and K2HPO4. The influence factors on single-stage extraction behavior of TC were optimized systematically, including the pH value, tie line length, and volume ratio. The optimal extraction efficiency of TC could reach above 95% when the volume ratio is higher than 1.5 and the tie line length is 30.52%. The multi-stage ATPE was also investigated by simulating a three-stage crosscurrent operation in test tubes. According to the TC isotherm curve and respective McCabe?Thiele diagrams, a predicted optimized scheme of the countercurrent multi-stage ATPE was determined. TC can be purified in the IL-rich top phase with a final extraction efficiency of 99% and a final TC concentration of 0.25 mg/mL, if a three- -stage [Bmim]Cl-K2HPO4 ATPE with volume ratio of 0.5 and tie line length of 30.52% was employed. Thus, the multi-stage extraction with small volume ratio is necessary to achieve a higher recovery yield, resulting in the reduction of the IL consumption.

scholarly journals Effects of global climate change on chlorophyll-a concentrations in a tropical aquatic system during a cyanobacterial bloom: a microcosm study

2017 ◽  
Vol 12 (3) ◽  
pp. 390 ◽  
Author(s):  
Meirielle Euripa Pádua de Moura ◽  
Lorraine Dos Santos Rocha ◽  
João Carlos Nabout
Keyword(s):  
Climate Change ◽  
Chlorophyll A ◽  
Elevated Temperatures ◽  
Cyanobacterial Bloom ◽  
Aquatic Environments ◽  
Precipitation Pattern ◽  
Chl A ◽  
Extreme Precipitation Events ◽  
Rainfall Frequency ◽  
The Impact

Recent studies have investigated the impact of climate change on aquatic environments, and Chlorophyll-a (Chl-a) concentration is a quick and reliable variable for monitoring such changes. This study evaluated the impact of rainfall frequency as a diluting agent and the effect of increased temperature on Chl-a concentrations in eutrophic environments during a bloom of cyanobacteria. This was based on the hypothesis that the concentration of Chl-a will be higher in treatments in which the rainfall frequency is not homogeneous and that warmer temperatures predicted due to climate change should favor higher concentrations of Chl-a. The experiment was designed to investigate three factors: temperature, precipitation and time. Temperature was tested with two treatment levels (22°C and the future temperature of 25°C). Precipitation was tested with four treatments (no precipitation, a homogeneous precipitation pattern, and two types of concentrated precipitation patterns). Experiments were run for 15 days, and Chl-a concentration was measured every five days in each of the temperature and precipitation treatments. The water used in the microcosms was collected from a eutrophic lake located in Central Brazil during a bloom of filamentous cyanobacteria (Geilterinema amphibium). Chl-a levels were high in all treatments. The higher temperature treatment showed increased Chl-a concentration (F=10.343; P=0.002); however, the extreme precipitation events did not significantly influence Chl-a concentrations (F=1.198; P=0.326). Therefore, the study demonstrates that future climatic conditions (projected to 2100), such as elevated temperatures, may affect the primary productivity of aquatic environments in tropical aquatic systems.

Operational Parameters and Back Propagation Neural Network (BPNN) Simulation Model of Integration Membrane Bioreactor (IMBR) Treating Sewage from Ship

2011 ◽  
Vol 356-360 ◽  
pp. 1042-1045
Author(s):  
Yue Shi ◽  
Liang Guo ◽  
Jun Zhou ◽  
Run Bai ◽  
Xin Li ◽  
...  
Keyword(s):  
Neural Network ◽  
Simulation Model ◽  
Membrane Bioreactor ◽  
Ph Value ◽  
Back Propagation ◽  
Influence Factors ◽  
Back Propagation Neural Network ◽  
Living Environment ◽  
Operational Parameters ◽  
Scale Experiment

Nowadays, in order to meet the new standard of IMO for sewage discharged from ship treatment, membrane bioreactor (MBR) was widely used in this field. In this study, a novel bioreactor named integration membrane bioreactor (IMBR) was used to treat sewage from ship. A lab scale experiment was conducted to find the best controlling strategy of operation. The results were as follows: The IMBR had strong adaptability and effluent stability under wide change in VLR which was from 1.2kg/m3.d to 4.3kg/m3.d; The HRT of the IMBR was suggested to be controlled around 6h; The IMBR operator was better in alkali-resistant and weaker in acid-proof, which implied the pH of suitable living environment for aerobic microbe should be higher than 6.5. At the same time, a simulation model of operational parameters was established based on theory of back propagation neural network (BPNN). The simulation model realizes prediction of which were the key impact factor and optimum operational parameters of the IMBR system. Each parameter influencing the performance of the reactor was compared using the method of partitioning connection weights (PCW). The weight of the influence factors was pH value> DO>influent COD in the experimental range.

Synthesis Method and its Influence Factors of Hydrotalcite-Like Compounds

2013 ◽  
Vol 690-693 ◽  
pp. 351-354 ◽  
Author(s):  
Hong Dan Xue ◽  
Fu Li Wang ◽  
Guo Li Li ◽  
Pu Liu ◽  
Yong Qing Bai ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Reduction Method ◽  
Ph Value ◽  
Raw Materials ◽  
Sol Gel ◽  
Synthesis Method ◽  
Influence Factors ◽  
Synthetic Methods ◽  
Molar Ratio ◽  
Temperature Reaction

Hydrotalcite-like compounds are a class of anionic lays or layed double hydroxiods (LDHs) which consists of alkalescence, anion-exchanges and memory effect. The synthetic methods of LDHs include coprecipitation, hydrothermal synthesis, mirowave radiation, ion exchange, sol-gel method, roasting reduction method, instant synthesis, etc.The molar ratio of raw materials, pH value,reaction temperature,reaction time and so on have a greater impact on the purity and crystallinity of the LDHs.

Research on Influence Factors of Bamboo Charcoal Adsorb Ammonia Nitrogen in Wastewater

2011 ◽  
Vol 356-360 ◽  
pp. 493-497 ◽  
Author(s):  
Zong Ning Li ◽  
Zong Qiang Zhu ◽  
Mei Na Liang ◽  
Hong Dong Qin ◽  
Yi Nian Zhu
Keyword(s):  
Ph Value ◽  
Influence Factors ◽  
Ammonia Nitrogen ◽  
Bamboo Charcoal ◽  
Solution Ph ◽  
Adsorption Ability ◽  
Adsorption Time ◽  
Initial Concentration ◽  
Adsorption Temperature ◽  
Better Than

The influences of adsorption temperature, adsorption time, dosing quantity, adsorption environment pH value, initial concentration and bamboo charcoal type on adsorption of bamboo charcoal adsorb ammonia nitrogen in wastewater are studied. The result shows that the maximum adsorption values are 1.1715 mg/g and 0.9115 mg/g respectively at 25°C and 40°C. Bamboo charcoal can easily absorb ammonia nitrogen at low temperature condition. 180 min is a suitable adsorption time. Increasing bamboo charcoal dosing quantity is helpful to improve efficiencies of ammonia nitrogen removal in wastewater, but the adsorption capacity is declining as bamboo charcoal dosing quantity increasing. Solution pH value has a great impact on the adsorbed amount, the adsorbed effect in alkaline solution is much better than in acid one’s. The adsorption ability of the moderate temperature bamboo charcoal is higher than the high temperature one’s.

The Influence Factors in Denitrifying Phosphorus Removal

2013 ◽  
Vol 401-403 ◽  
pp. 2084-2087
Author(s):  
Ming Fen Niu ◽  
Si Li ◽  
Hong Jing Jiao ◽  
Jian Wei ◽  
Yuan Yang Sun ◽  
...  
Keyword(s):  
Retention Time ◽  
Phosphorus Removal ◽  
Ph Value ◽  
Influence Factors ◽  
Volume Ratio ◽  
Wastewater Sludge ◽  
Practical Application ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Denitrifying Phosphorus Removal

Denitrifying phosphorus removal can be achieved with the same matrix simultaneous nitrogen and phosphorus removal，is a hot topic of abroad study biological wastewater treatment，This is discussed the Influence factors of anoxic tank NO3- load, dissolved oxygen and the volume ratio of aerobic tank and anoxic tank, pH value of wastewater, sludge retention time (SRT), hydraulic retention time (HRT), mixed liquor suspended solids (MLSS) and temperature on denitrifying phosphorus removal, for denitrifying phosphorus removal process simulation, experimental research and practical application provides a reference and basis.

Analysis of Influence Factors on Heavy Metal Release from Mine Waste Rock in Fu Xin Mine Area

2010 ◽  
Vol 29-32 ◽  
pp. 2570-2575
Author(s):  
Bing Liang ◽  
Li Guo Jiang ◽  
Xiu Sheng Lu
Keyword(s):  
Heavy Metal ◽  
Ph Value ◽  
Mine Waste ◽  
Influence Factors ◽  
Waste Rock ◽  
Metal Release ◽  
Mine Waste Rock ◽  
Leaching Solution ◽  
Heavy Metal Elements ◽  
Heavy Metal Release

For analysis of influence factors on heavy metal release from different weathering mine waste rock in Fu Xin mine area under the effect of rain water leaching, the materials which come from mine waste rock pile nearby Xin Qiu mine is collected and then process a serial leaching experiments. The initial PH value of leaching solution and experiment temperature have been selected to as influencing factors according to rainfall and weather condition of Fuxin mining area. The concentration of five heavy metal elements: Cd, Cr, Cu, Mn and Pb are tested in leaching solutions. The results show that the constituent characteristics of stratum rock is a major factor influenced on leaching solutions and heavy metal release. The weakly acidic leaching solution becomes to weakly alkaline after leaching the waste rock. The quantities of different heavy metal release represent disparate rules, influenced by distinct weathering degree. Concentrations of Cd and Cr increase with the leaching solution's pH value variation while Cu, Mn and Pb decreased. Higher temperature leads more heavy metal elements release from the waste rock.

Oxidative Decolorization of Azo Dyes with Copper Phthalocyanine Supported Mg-Al Hydrotalcites

2016 ◽  
Vol 703 ◽  
pp. 306-310
Author(s):  
Min Hong Xu ◽  
Jian Li Ma ◽  
Meng Xia Qian ◽  
Hui Na Qin
Keyword(s):  
Molecular Structure ◽  
Methylene Blue ◽  
Methyl Orange ◽  
Azo Dyes ◽  
Acidic Solution ◽  
Copper Phthalocyanine ◽  
Ph Value ◽  
Influence Factors ◽  
Amido Black ◽  
Initial Ph

Oxidative decolorization of azo dyes with a heterogeneous catalyst copper phthalocyanine supported Mg-Al hydrotalcites was studied and the influence factors such as initial pH value, temperature, H2O2 and CuPc-LDHs/H2O2 system were discussed. The results indicated that acidic solution and high temperature were conducive to oxidative decoloration of methyl orange. CuPc-LDHs/H2O2 system showed excellent oxidative decoloration capacity to remove azo dyes. The effects of oxidative decolorization of azo dyes were related to the molecular structure and weight of azo dyes. Oxidative decoloration effects followed the order as congo red > amido black > methyl blue> methyl orange> methylene blue.

scholarly journals Adsorption of Cu2+, Zn2+, and Ni2+ ions onto the adsorbent prepared from fluid catalytic cracking spent catalyst fines and diatomite

2019 ◽  
Vol 68 (5-6) ◽  
pp. 201-208
Author(s):  
Shu Qin Zheng ◽  
Ting Wang ◽  
Cheng Yang ◽  
Pei Qing Zhang ◽  
Si Cheng Liu
Keyword(s):  
Catalytic Cracking ◽  
Metal Ion ◽  
Room Temperature ◽  
Ph Value ◽  
Influence Factors ◽  
Fluid Catalytic Cracking ◽  
Spent Catalyst ◽  
Adsorption Data ◽  
Freundlich Adsorption Isotherm ◽  
Adsorption Desorption

An adsorbent prepared from fluid catalytic cracking (FCC) spent catalyst fines and diatomite, and its adsorption of Cu2+, Zn2+, and Ni2+ ions were investigated. The adsorbent was characterized by XRD, SEM, and N2 adsorption-desorption techniques. The results showed that the specific surface area and pore volume of adsorbent increased with the increase in FCC spent catalyst fines. The influence factors on the adsorption of the adsorbents were studied. The suitable adsorption conditions were: pH value of 5.0, ratio of solid to liquid of 1 : 600 (g:ml), adsorption time of 4 h, room temperature. The adsorption of metal ions varied with the type of metal cations. The adsorption isotherms suggested that the sequence of the adsorption efficiency was Cu2+ > Zn2+ > Ni2+. The amount of Cu2+, Zn2+, and Ni2+ metal ion adsorbed onto the adsorbent was 49.17 mg g–1, 46.83 mg g–1, and 35.72 mg g–1, respectively. The adsorption data of Cu2+, Zn2+, and Ni2+ ions fitted well with the Freundlich adsorption isotherm model.

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