Rasool Bux Mahar

Ultrasonic dyeing of cellulose nanofibers.

Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing.

Modeling and simulation of landfill gas production from pretreated MSW landfill simulator

The cumulative landfill gas (LFG) production and its rate were simulated for pretreated municipal solid waste (MSW) landfill using four models namely first order exponential model, modified Gompertz model, single component combined growth and decay model and Gaussian function. Considering the behavior of the pretreated MSW landfill, a new multi component model was based on biochemical processes that occurring in landfilled pretreated MSW. The model was developed on the basis of single component combined growth and decay model using an anaerobic landfill simulator reactor which treats the pretreated MSW. It includes three components of the degradation i.e. quickly degradable, moderately degradable and slowly degradable. Moreover, the developed model was statistically analyzed for its goodness of fit. The results show that the multi components LFG production model is more suitable in comparison to the simulated models and can efficiently be used as a modeling tool for pretreated MSW landfills. The proposed model is likely to give assistance in sizing of LFG collection system, generates speedy results at lower cost, improves cost-benefit analysis and decreases LFG project risk. It also indicates the stabilization of the landfill and helps the managers in the reuse of the landfill space. The proposed model is limited to aerobically pretreated MSW landfill and also requires the values of delay times in LFG productions from moderately and slowly degradable fractions of pretreated MSW.

Removal of lead from aqueous solution using polyacrylonitrile/magnetite nanofibers

Lead is known for its toxic and non-biodegradable behavior. The consumption of lead-contaminated water is one of the major threat the world is facing nowadays. In this study, polyacrylonitrile (PAN) and magnetite (Fe3O4) composite nanofiber adsorbent was developed for Pb2+ removal in batch mode. The synthesis was done by a simple and scalable process of electrospinning followed by chemical precipitation of Fe3O4. The nanofibers thus obtained were characterized through FTIR, zeta potential analyzer, and scanning electron microscope (SEM) and were analyzed for their adsorption capability for Pb2+ ions. The amount of metal ion adsorbed was influenced by the initial metal ion concentration, the time the adsorbent was in contact, the amount of nanofiber, and the pH of the solution. The experimental data fitted well with pseudo 2nd-order and Langmuir adsorption isotherm model. The nanofibers showed high adsorption capability and could be recommended for Pb2+ removal successfully.

Fe3O4 nanoparticles facilitated anaerobic digestion of organic fraction of municipal solid waste for enhancement of methane production

ABSTRACT Since the emergence of zero waste concept, efficient waste recycling system and recovery of energy from the waste materials become challenging tasks globally. Municipal solid waste (MSW) is considered as one of a potential sources of energy. In the present study, bio-compactable iron oxide (Fe3O4) nanoparticles (NPs) were synthesized by hydrothermal method. These NPs were characterized by using atomic force microscopy (AFM), energy dispersive x-ray (EDX), and scanning electron microscopy (SEM) for size determination and surface morphology. The organic fraction of MSW (OFMSW) such as food waste (FW) was utilized as a substrate in this study. The anaerobic digestion of OFMSW in batch test was carried out under mesophilic temperature (37 ± 0.5°C). Four different concentrations of Fe3O4 NPs i.e 50mg/L, 75mg/L, 100mg/L, and 125mg/L were added in each batch test. It was observered that 75mg/L yielded maximum CH4 and followed by 50mg/L.

The seasonal evolution of fruit, vegetable and yard wastes by mono, co and tri-digestion at Hyderabad, Sindh Pakistan

The contribution of biowastes in municipal solid waste (MSW) is increasing day by day and being dumped in open atmosphere along with other wastes in every city of Pakistan. This study was formulated to evaluate the feasibility of biowastes such as fruit, vegetable and yard wastes of different seasons individual and mixing at different ratios to optimize methane production at Hyderabad Sindh, Pakistan. Batch digestion of selected samples was conducted for 40 days under mesophilic condition. Methane yield of individual fruit, vegetable and yard wastes (FrVYW) of summer and winter season was obtained in the range of 0.36-0.40 L/g VS and 0.39-0.44 L/g VS added respectively. The results of co-digestion of FrVYW of summer and winter season were observed in the range of 0.42-0.45 L/g VS added and 0.46 to 0.54 L/g VS added respectively. The results of tri-digestion of FrVYW of summer and winter season were achieved in the range of 0.46-0.53 L/g VS added and 0.56-0.62 L/g VS added respectively. Findings of study showed that methane production potential of tri-digestions were highest than all of others and that of co-digestion were higher than mono-digestion of FrVYW. Overall results of study concluded that tri-digestion of FrVYW at the equal blending ratio reported highest methane potential. Therefore, the study recommended that tri-digestion of FrVYW at equal mixing ratio is an optimal ratio for anaerobic digestion process to yield maximum methane production from FrVYW.

Efficient Removal of Reactive Blue 19 Dye by Co-Electrospun Nanofibers

The present work demonstrates the new nanofiber mats prepared through 20 co-electrospinning of two different polymers i.e. corn protein namely Zein and Nylon-6. The 21 composite nanofiber membrane was used as an effective adsorbent material for the removal of 22 toxic reactive dye i.e. Reactive Blue 19 (RB 19) from water solution. These co-electrospun nanofibers 23 had good mechanical strength compared to zein nanofibers alone. Experimental results suggested 24 that zein/nylon nanofibers have greater potential for total removal of RB19 at room temperature 25 within 10 min of contact time from aqueous solution. The maximum capacity was found to be 70 26 mg/g of nanofibers. The mechanism of RB19 removal on proposed nanofibers is mainly through 27 hydrogen bond and electrostatic means. 28

Improving Methane Production through Co-Digestion of Canola Straw and Buffalo Dung by H2O2 Pretreatment

In this study an effect of acidic pretreatment on the CS (Canola Straw) and BD (Buffalo Dung) by anaerobic co-digestion was investigated. H2O2 (Hydrogen Peroxide) is a mainly accustomed reagent, used as a bleaching agent in the different industries such as paper and wood. In the present study, it was used as a pretreatment chemical at varying concentrations in batch reactors. The co-digestion of CS and BD was carried out in SAMPTS (Semi-Automatic Methane Potential Test System) at mesophilic (37±1oC) conditions. The CS was pretreated in glass bottles with different concentrations of the H2O2 for seven days. The inoculum used in the present study was an effluent of the CSTR (Continuous Stirred Tank Reactor), which was treating BD at mesophilic conditions. The specific methane production from the codigestion of canola straw and BD, by the pretreatment of H2O2 at concentrations of 0.5, 1.0, and 1.5% were 530.8, 544.5, and 510.3 NmL CH4 g/VS, respectively. The significant reduction in the volatile solids of CS was observed at the optimum pretreatment of 1.0% H2O2.

Environmental Policies for New Road Network of Pakistan to Control Air Emissions

Most of the developing countries face a lack of infrastructure facilities and the road transport network is one of them. In this chapter, first Strategic Environmental Assessment (SEA) is carried out for proper combination of policies for economic and environmental impacts of air emissions. Second, for the estimation of economic and environmental impacts of this project, a multiregional Computable General Equilibrium (CGE) model is proposed. Third, impacts of the new road network that connects south and northwest of Pakistan are analyzed using CGE model. It is found that construction of this project is going to change the industrial structure, especially in production of manufacturing sector, and it will also change the Equivalent Variation (EV). It is also observed that most of the economic and environmental impacts of air emissions appeared in northwest part of Pakistan. Finally, the combination of policies for desired economic and environmental impacts of air emissions in project is proposed