Brine is a solution of salt （usually sodium chloride） in water. In different contexts, brine may refer to salt solutions ranging from about 3.5% （a typical concentration of seawater, or the lower end of solutions u...Brine is a solution of salt （usually sodium chloride） in water. In different contexts, brine may refer to salt solutions ranging from about 3.5% （a typical concentration of seawater, or the lower end of solutions used for brining foods） up to about 26% （a typical saturated solution, depending on temperature）. Adsorption onto activated carbon is the most widespread technology for the removal of pollutants from water and wastewaters. In this study, continuous fixed-bed-column systems were investigated. The adsorbents which authors use are： spruce （Picea abies） untreated, spruce modified by autohydrolysis. The column systems were filed with biomass at various initial dye concentrations, flow rates and bed-depths. The column kinetics of MB （Methylene Blue） adsorption on spruce （Picea abies） untreated, spruce modified by autohydrolysis was simulated. Economies arise when the facility that can use such adsorption materials is near a source of a lignocellulosic waste as agricultural residues, thus saving transportation cost and contributing to industrial ecology at local level.展开更多
Adsorption is an important process in wastewater treatment,and conversion of waste materials to adsorbent offers a solution to high material cost related to the use of commercial activated carbon.This study investigat...Adsorption is an important process in wastewater treatment,and conversion of waste materials to adsorbent offers a solution to high material cost related to the use of commercial activated carbon.This study investigated the adsorption behaviour of Reactive Black 5（RB5）and methylene blue（MB）onto activated carbon produced from textile sludge（TSAC）.The activated carbon was synthesized through chemical activation of precursor followed with carbonization at 650℃ under nitrogen flow.Effects of time（0–200 min）,pH（2–10）,temperature（25–60℃）,initial dye concentration（0–200 mg·L^-1）,and adsorbent dosage（0.01–0.15 g）on dye removal efficiency were investigated.Preliminary screening revealed that TSAC synthesized via H2SO4activation showed higher adsorption behaviour than TSAC activated by KCl and ZnCl2.The adsorption capacity of TSAC was found to be 11.98 mg·g^-1（RB5）and 13.27 mg·g^-1（MB）,and is dependent on adsorption time and initial dye concentration.The adsorption data for both dyes were well fitted to Freundlich isotherm model which explains the heterogeneous nature of TSAC surface.The dye adsorption obeyed pseudo-second order kinetic model,thus chemisorption was the controlling step.This study reveals potential of textile sludge in removal of dyes from aqueous solution,and further studies are required to establish the applicability of the synthesized adsorbent for the treatment of waste water containing toxic dyes from textile industry.展开更多
Spring wheat (Triticum aestivum L. cv. Dingxi No. 8654) was treated with twoconcentrations of atmospheric CO_2 (350 and 700 μmol mol^(-1)), two levels of soil moisture(well-watered and drought) and five rates of nitr...Spring wheat (Triticum aestivum L. cv. Dingxi No. 8654) was treated with twoconcentrations of atmospheric CO_2 (350 and 700 μmol mol^(-1)), two levels of soil moisture(well-watered and drought) and five rates of nitrogen fertilizer (0, 50, 100, 150, and 200 mgkg^(-1) soil) to study the atmospheric CO_2 concentration effect on dry matter accumulation and Nuptake of spring wheat. The effects of CO_2 enrichment on the shoot and total mass depended largelyon soil nitrogen level, and the shoot and total mass increased significantly in the moderate to highN treatments but did not increase significantly in the low N treatment. Enriched CO_2 concentrationdid not increase more shoot and total mass in the drought treatment than in the well-wateredtreatment. Thus, elevated CO_2 did not ameliorate the depressive effects of drought and nitrogenstress. In addition, root mass decreased slightly and root/shoot ratio decreased significantly dueto CO_2 enrichment in no N treatment under well-watered condition. Enriched CO_2 decreased shoot Ncontent and shoot and total N uptake; but it reduced root N content and uptake slightly. Shootcritical N concentration was lower for spring wheat grown at 700 μmol mol^(-1) CO_2 than at 350μmol mol^(-1) CO_2 in both well-watered and drought treatments. The critical N concentrations were16 and 19 g kg^(-1) for the well-watered treatment and drought treatment at elevated CO_2 and 21 and26 g kg^(-1) at ambient CO_2, respectively. The reductions in the movement of nutrients to theplant roots through mass flow due to the enhancement in WUE (water use efficiency) and the increasein N use efficiency at elevated CO_2 could elucidate the reduction of shoot and root Nconcentrations.展开更多
In aquaculture,it is important to estimate in advance how much food cultured animals would take.The rate of food consumption by cultured animals to available food amount is defined as the food intake rate(FIR) in this...In aquaculture,it is important to estimate in advance how much food cultured animals would take.The rate of food consumption by cultured animals to available food amount is defined as the food intake rate(FIR) in this paper.To some extents,FIR reflects the quality of food,the health of cultured animals and the delivery efficiency.In practice,it is difficult to estimate in advance the accurate quantity of food that cultured animal needs.Usually,food is provided more than the need by animals,causing excess food that may pollute water and environment.Our experiments in past years show that FIR at 80% is recommended.展开更多
Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment.Bio-sorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and...Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment.Bio-sorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution.The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species.The biosorption property of Streptomyces VITSVK5 spp.was investigated by absorbing heavy metals Cadmium (Cd) and Lead (Pb).Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L-1,cadmium 3.1±0.3μg L-1,zinc 8.4±2.6μg L-1 and copper 0.3±0.1μg L-1,whereas mercury was well below the detection limit.The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated.The optimum pH for maximal biosorption was 4.0 for Cd (II) and 5.0 for Pb (II) with 41% and 84% biosorption respectively.The biosorbent dosage was optimized as 3 g L-1 for both the trace metals.Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl (–COOH),hydroxyl (–CHOH) and amine (–NH2) groups of biomass with the metal ions.This could be mainly involved in the biosorption of Cd (II) and Pb (II) onto Streptomyces VITSVK5 spp.The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.展开更多
文摘Brine is a solution of salt （usually sodium chloride） in water. In different contexts, brine may refer to salt solutions ranging from about 3.5% （a typical concentration of seawater, or the lower end of solutions used for brining foods） up to about 26% （a typical saturated solution, depending on temperature）. Adsorption onto activated carbon is the most widespread technology for the removal of pollutants from water and wastewaters. In this study, continuous fixed-bed-column systems were investigated. The adsorbents which authors use are： spruce （Picea abies） untreated, spruce modified by autohydrolysis. The column systems were filed with biomass at various initial dye concentrations, flow rates and bed-depths. The column kinetics of MB （Methylene Blue） adsorption on spruce （Picea abies） untreated, spruce modified by autohydrolysis was simulated. Economies arise when the facility that can use such adsorption materials is near a source of a lignocellulosic waste as agricultural residues, thus saving transportation cost and contributing to industrial ecology at local level.
基金the Ministry of Higher Education,Malaysia(MOHE)for the financial supports received under University Grant(08H05)and Fundamental Research Grant Scheme(4F872)Universiti Teknologi Malaysia for the GUP grant No.17H65the support to the main author,Wong Syie Luing,in the form of Post-Doctoral Fellowship Scheme for the project"Catalytic Cracking of Low Density Polyethylene Waste to Liquid Fuels in Fixed Bed Reactor"
文摘Adsorption is an important process in wastewater treatment,and conversion of waste materials to adsorbent offers a solution to high material cost related to the use of commercial activated carbon.This study investigated the adsorption behaviour of Reactive Black 5（RB5）and methylene blue（MB）onto activated carbon produced from textile sludge（TSAC）.The activated carbon was synthesized through chemical activation of precursor followed with carbonization at 650℃ under nitrogen flow.Effects of time（0–200 min）,pH（2–10）,temperature（25–60℃）,initial dye concentration（0–200 mg·L^-1）,and adsorbent dosage（0.01–0.15 g）on dye removal efficiency were investigated.Preliminary screening revealed that TSAC synthesized via H2SO4activation showed higher adsorption behaviour than TSAC activated by KCl and ZnCl2.The adsorption capacity of TSAC was found to be 11.98 mg·g^-1（RB5）and 13.27 mg·g^-1（MB）,and is dependent on adsorption time and initial dye concentration.The adsorption data for both dyes were well fitted to Freundlich isotherm model which explains the heterogeneous nature of TSAC surface.The dye adsorption obeyed pseudo-second order kinetic model,thus chemisorption was the controlling step.This study reveals potential of textile sludge in removal of dyes from aqueous solution,and further studies are required to establish the applicability of the synthesized adsorbent for the treatment of waste water containing toxic dyes from textile industry.
基金the National Key Basic Research Support Foundation(NKBRSF)of China(No.G1999011708) the Guangxi University Science funds,China(No.1701).
文摘Spring wheat (Triticum aestivum L. cv. Dingxi No. 8654) was treated with twoconcentrations of atmospheric CO_2 (350 and 700 μmol mol^(-1)), two levels of soil moisture(well-watered and drought) and five rates of nitrogen fertilizer (0, 50, 100, 150, and 200 mgkg^(-1) soil) to study the atmospheric CO_2 concentration effect on dry matter accumulation and Nuptake of spring wheat. The effects of CO_2 enrichment on the shoot and total mass depended largelyon soil nitrogen level, and the shoot and total mass increased significantly in the moderate to highN treatments but did not increase significantly in the low N treatment. Enriched CO_2 concentrationdid not increase more shoot and total mass in the drought treatment than in the well-wateredtreatment. Thus, elevated CO_2 did not ameliorate the depressive effects of drought and nitrogenstress. In addition, root mass decreased slightly and root/shoot ratio decreased significantly dueto CO_2 enrichment in no N treatment under well-watered condition. Enriched CO_2 decreased shoot Ncontent and shoot and total N uptake; but it reduced root N content and uptake slightly. Shootcritical N concentration was lower for spring wheat grown at 700 μmol mol^(-1) CO_2 than at 350μmol mol^(-1) CO_2 in both well-watered and drought treatments. The critical N concentrations were16 and 19 g kg^(-1) for the well-watered treatment and drought treatment at elevated CO_2 and 21 and26 g kg^(-1) at ambient CO_2, respectively. The reductions in the movement of nutrients to theplant roots through mass flow due to the enhancement in WUE (water use efficiency) and the increasein N use efficiency at elevated CO_2 could elucidate the reduction of shoot and root Nconcentrations.
基金Supported by the National Science Foundation of China, Key Lab. of Marine Ecology & Environment, Ministry of Education, Ocean University of Chinathe National High-Technology R&D Program of China (863 Program, No. 2006AA09Z418)
文摘In aquaculture,it is important to estimate in advance how much food cultured animals would take.The rate of food consumption by cultured animals to available food amount is defined as the food intake rate(FIR) in this paper.To some extents,FIR reflects the quality of food,the health of cultured animals and the delivery efficiency.In practice,it is difficult to estimate in advance the accurate quantity of food that cultured animal needs.Usually,food is provided more than the need by animals,causing excess food that may pollute water and environment.Our experiments in past years show that FIR at 80% is recommended.
文摘Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment.Bio-sorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution.The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species.The biosorption property of Streptomyces VITSVK5 spp.was investigated by absorbing heavy metals Cadmium (Cd) and Lead (Pb).Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L-1,cadmium 3.1±0.3μg L-1,zinc 8.4±2.6μg L-1 and copper 0.3±0.1μg L-1,whereas mercury was well below the detection limit.The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated.The optimum pH for maximal biosorption was 4.0 for Cd (II) and 5.0 for Pb (II) with 41% and 84% biosorption respectively.The biosorbent dosage was optimized as 3 g L-1 for both the trace metals.Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl (–COOH),hydroxyl (–CHOH) and amine (–NH2) groups of biomass with the metal ions.This could be mainly involved in the biosorption of Cd (II) and Pb (II) onto Streptomyces VITSVK5 spp.The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.
