Construction of double tube granular sludge microbial fuel cell and its characteristics and mechanism of azo dye degradation

Environmental Science and Pollution Research - Microbial fuel cells (MFCs) can obtain electrical energy from extensive organic matter and complete wastewater treatment at the same time. The...     

Adsorptive removal of direct dyes by PEI-treated peanut husk biomass: Box–Behnken experimental design

This paper reports the application of Box-Behnken experimental design to illustrate the adsorption of direct dyes (Indosol Black NF and Indosol Orange RSN) using polyethyleneimine (PEI)-treated peanut husk biomass. The effect of three independent variables (initial dyes concentration, biosorbent dose and pH) was investigated during the study. Maximum biosorption capacity (141 and 98.2 mg/g) of PEI-pretreated biomass was achieved with 200 mg/L initial dye concentration and 0.05 g/50 mL biomass dose for Indosol Black NF and Indosol Orange RSN, respectively. Acidic pH was found to be favourable for maximum dyes removal. Characterisation of biosorbent was carried out through Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy, thermogravimetric analysis (TGA) and point of zero charge determination. FT-IR analyses confirmed the involvement of carboxylic and carbonyl groups. The desorption study was also conducted to check out the possibility of regeneration of dyes and adsorbent and it was found that 51.58 and 76.6% of Indosol Black NF and Indosol Orange RSN, respectively, can be desorbed from the loaded biosorbent by using 1 M NaOH solution. The results indicated that PEI-treated peanut husk biomass can be used as an efficient biosorbent for the removal of Indosol Black NF and Indosol Orange RSN dyes from aqueous solutions.     

Magnetic particles precipitated onto wheat husk for removal of methyl blue from aqueous solution

Magnetic particles prepared via co-precipitation and impregnated onto wheat husk (MN-WH) were used for the removal of methyl blue (MB) from aqueous solution. Experiments were conducted in a batch mode for optimization regarding pH, contact time, adsorbent dose, initial dye concentrations, and temperature. Maximum adsorption (98%) was achieved at pH 5. The adsorption data were fitted into pseudo-first, pseudo-second, intraparticle diffusion, and Elovich equation revealing that adsorption followed pseudo-second-order kinetics. The four most common isotherm models, i.e. the Langmuir, Freundlich, Tempkin, and Dubinin–Radushkevich (D–R), were used to evaluate the data, with the best fit to a Langmuir isotherm (R² = 0.996), followed by a Freundlich isotherm (R² = 0.995), indicating monolayer adsorption of MB on the surface of MN-WH. Thermodynamic parameters calculated from the Van't Hoff equation revealed that the adsorption is exothermic (ΔHº = ?19.7 kJ mol^?1).     

Microwave-Induced Modification of Physical and Functional Characteristics and Antioxidant Potential of Alkali-Soluble Cell Wall Polysaccharides of Nelumbo nucifera Rhizome

Journal of Polymers and the Environment - The alkali-soluble cell wall polysaccharides (CWPs), extracted from Nelumbo nucifera rhizome flour (NNRF), were treated with microwave radiation to modify...     

Removal of Novacron Golden Yellow dye from aqueous solutions by low-cost agricultural waste: Batch and fixed bed study

The present work describes the removal of Novacron Golden Yellow (NGY) dye from aqueous solutions using peanut hulls. The experiments were performed with native, pretreated and immobilised forms of peanut hulls. The effect of various operational parameters (pH, biosorbent dose, initial dye concentration and temperature etc.) was explored during batch study. NGY showed maximum removal at low pH and low biosorbent dose. High initial dye concentration facilitated the biosorption process. Maximum dye removal with native, pretreated and immobilised biomass was found to be 35.7, 36.4 and 15.02 mg/g respectively. The experimental data were subjected to different kinetic and equilibrium models. The kinetic data confirmed the fitness of pseudo-second-order rate law for NGY biosorption. The equilibrium modelling was carried out by Freundlich, Langmuir and Temkin models. The isothermal data of NGY removal were best described by Freundlich adsorption isotherm. Negative values of Free energy change (Δ G⁰) for NGY with native and pretreated biomass depicted the spontaneous nature of biosorption process. In column mode, the effects of bed height, flow rate and initial dye concentrations were optimised. Maximum NGY biosorption (7.28 mg/g) was observed with high bed height, low flow rate and high initial concentration in continuous mode. Bohart–Adams model best fitted to the data obtained from column studies. The results indicated that the peanut hulls could be used effectively for the removal of dyes containing wastewater.     

Recent Trends and Patterns of Nutrient Concentrations in Small Agricultural Streams in Sweden

Long-term median total phosphorus (TotP) and total nitrogen (TotN) concentrations were 0.08 and 5.5 P/N (mg L^-1), respectively, in 10 agricultural streams monitored since 1988 in Sweden. The areas ofthe respective catchments are 2–20 km². The period 1992/2002 was characterised by stable hydrological conditions without any flow trends in nearly all of the streams. The highest average TotP concentration, 0.17 mg P L^-1, was found in a small agriculturalstream in the largest Swedish agricultural plain. The soil texture is here characterised by a large specific surface area of the soil particles, and the agriculture by cereal production. The second highestaverage TotP concentration, 0.14 mg P L ^-1, was measured in the surface water from a catchment characterised partly by clay soils andby production of potato, spring cereals and grass. This catchment had twice as many fields with a calculated high risk for P losses comparedwith another monitored catchment in the same watershed (River Rönneå). There was a significant downward TotP trend during 1992/2002 of 0.0012 mg P L^-1 yr^-1 (Sen's slope estimator) in the catchment where many fields risk P losses and which had a reduced P manure application rate of –20% during 1995/2000. In recent years practically no manure has been spread during autumn. Bypass flow of nitrate through one soil has been suggested to influence the LOWESS (LOcally WEighted Scatterplot Smothing) fitting curve of TotN. Total nitrogen concentration decreased in most of the catchment. The average downward slope was similar to a general TotN reduction of 0.069 mg N L^-1 yr^-1. During the period 1992/2002 this was equal to slightly more than 10 per cent. Cultivation of catch crops wasrelatively uncommon until 2002, but this practice is expected to expandto larger areas during 2003 and in the future.     

Ag@MnxOy: an effective catalyst for photo-degradation of rhodamine B dye

Environmental Chemistry Letters - Water pollution by the textile industry is a major issue. Therefore, there is a need for methods to remove organic dyes from industrial effluents. Various...     

The use of personalised social marketing to foster voluntary behavioural change for sustainable travel and lifestyles

Changing public attitudes and behaviour is key to achieving the UK target of a 60% reduction in carbon dioxide emissions by 2050. Top-down campaigns that have provided information to a passive public have not necessarily resulted in pro-environmental behavioural change. This paper examines the use of a personalised social marketing approach to engage the public in changing their personal travel. It provides the results of a project in the City of York to foster voluntary travel behavioural change. Using face-to-face discussions, personalised information and incentives, a statistically significant reduction in car use and an increase in cycling and the use of public transport were achieved over a six-month period. However, this change was not sustained 12 months later. The paper explores the contrasting perspectives on behavioural change and examines the possible lessons that can be learnt to foster voluntary behavioural change in other aspects of household consumption.     

A targeted social marketing approach for community pro-environmental behavioural change

Community-level initiatives will play a key role in meeting greenhouse gas reduction targets. This paper examines the experience gained in applying a targeted social marketing approach to foster local-scale community pro-environmental behavioural change in the City of York, UK. This involved determining the neighbourhood carbon footprint, identifying residents that had access to appropriate infrastructure and were receptive to green issues. Six community teams were recruited from the selected neighbourhoods and provided with information, advice and mentoring on how to reduce their carbon footprint over a six-month period. A statistically significant reduction in carbon emissions was achieved. Each participant achieved a mean reduction in their carbon footprint of 2.0 tonnes of CO₂e/year. The largest reductions were achieved in the areas of shopping and home energy. In addition, it helped to foster community spirit. Based on the experience gained from implementing this approach, a cost-effective model of community engagement is proposed.