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In this study, levulinic acid (LA) was produced from rice straw biomass in co-solvent biphasic reactor system consisting of hydrochloric acid and dichloromethane organic solvent. The modified protocol achieved a 15% wt LA yield through the synergistic effect of acid and acidic products (auto-catalysis) and the designed system allowed facile recovery of LA to the organic phase. Further purification of the resulting extractant was achieved through traditional column chromatography, which yielded a high purity LA product while recovering ∼85% wt. Upon charcoal treatment of the resultant fraction generated an industrial grade target molecule of ∼99% purity with ∼95% wt recovery. The system allows the solvent to be easily recovered, in excess of 90%, which was shown to be able to be recycled up to 5 runs without significant loss of final product concentrations. Overall, this system points to a method to significantly reduce manufacturing cost during large-scale LA preparation.

The present study is motivated by the need to decouple economic growth from environmental degradation given the new wave of chase for higher economic growth trajectories comes with its environmental cost implications, especially among developing blocs like the Emerging 7 (E7) countries. There is a consistent trade-off between economic growth versus environmental quality. Government apparatus are perpetually on the chase for low-carbon emission policies via the pursuit for green economy. To this end, this present study extends the conventional environmental Kuznets curve (EKC) argument by incorporating the role of institution in emerging industrialized economies (E7) and using second-generation panel analysis methods like mean group (MG), augmented mean group (AMG), common correlated effects mean group (CCEMG), and the Dumitrescu and Hurlin causality test for more robust estimates and inferences. To this end, we explore the long-run and causality relationship between economic growth, quadratic form of economic growth, institutional quality, trade flow, investment in energy sector, and financial development in an EKC environment. Empirical analysis established a long-run equilibrium relationship among the outlined variables over the study period. The long-run regression shows the presence of EKC in the E7. Thus, suggesting the preference for GDP growth over environmental quality at the earlier stage of growth curve. Interestingly, investment in energy, trade flow dynamics across the blocs, and financial development dampens the detrimental effect of environmental pollution as we observed negative relationship with the ecological footprint. On the contrary, quality of institution is weak as institutional quality increase (worsen) the quality of environment in the E7 economies. From a policy perspective, this current study proposed the need for more stringent environmental treaties and regulations and promotion of green economy without compromising economic growth. In the conclusion part of the study, more details and specifics about the policy blueprint are presented.

Abstract Enhancing microalgae biomass productivity through different abiotic and environmental factors optimization is crucial. Design of experimental (DOE) methodology using Taguchi orthogonal array (OA) was studied to evaluate the specific influence of eight important factors (light, pH, temperature, carbon concentration, nitrates, phosphates, magnesium ion concentration and carbon source) on the biomass production using three levels of factor (2 1 × 3 7 ) variation with experimental matrix [L 18 -18 experimental trails]. All the factors were assigned with three levels except light illumination (2 1 ). Substantial influence on biomass productivity is observed with carbon concentration contributing 16.8%, followed by nitrates 12.8% and light 9.3%. Experimental setup eight (Light, pH-8.5, Temperature 25°C, Carbon concentration 10 g/l, nitrates 1.5 g/l, phosphates 0 g/l, magnesium 150 mg/l, Carbon source (glucose)) showed maximum biomass growth (5.26 g/l) and good substrate degradation (63%, COD removal efficiency) contributing to carbohydrate production (257 mg/g biomass) which is further converted to lipids (20% Total lipid and 10% Neutral lipids). Chlorophyll ( a , b ), carbohydrates composition, FAME analysis for lipid percentage were monitored during process operation. Elemental analysis reveals that the carbon to hydrogen and oxygen ratio present in dried algal biomass can be hydrothermally liquefied (HTL) to produce biocrude.

Abstract A process engineering strategy was developed for cultivation of high density biomass of Chlorella sp. FC2 with improved productivity under photoautotrophic condition. The process engineering strategy involved a combinatorial approach of: (i) optimization of CO2 concentration in the inlet gas stream & aeration rate; (ii) growth kinetic driven feeding recipe for limiting nutrients; and (iii) dynamic increase in light intensity. The strategy was tested by growing the cells on laboratory grade BG11 medium. With an attempt to reduce the cultivation cost, the growth performance of the organism was then evaluated on commercial grade BG11 medium. Finally, hydrothermal liquefaction was carried out for direct conversion of microalgal slurry into bio-crude oil. Cultivation on laboratory grade BG11 medium resulted in biomass titer and overall productivity of 8.41 g L−1 and 575.9 mg L−1 day−1 respectively. Significant improvement in biomass titer (13.23 g L−1) and overall productivity (731.6 mg L−1 day−1) was observed when grown on commercial grade BG11 medium. Higher fraction of hydrocarbon in the bio-crude oil depicted better oil quality. Thermal gravimetric analysis revealed that maximum distillate fraction lies within the boiling point range of 200–300 °C which is suitable for conversion into diesel oil, jet fuel, and fuel for stoves.

Abstract Small hydropower projects (SHPs), though generally considered more environmentally benign and socially acceptable as compared to large projects, yet their overall sustainability is under suspicion in the Himalayan regions. Almost all SHPs in this region are being developed as run of the river mode which generally causes less/no submergence and quite less displacement of people as compared to large reservoir based hydropower production mode. However, in the absence of proper planning and monitoring mechanism, these projects are causing implacable tunnelling of hills, choking of streams, conversion of streams into dry ditches and long term socio-environmental impacts. This paper presents a SHP development study from hydro rich Beas river basin of Himachal Pradesh, a state nestled in western Himalayan region of India. In depth field studies, focus group discussions with the project affected people and interaction with project proponents of five SHPs in this region suggest that sustainability issues with respect to SHPs are not small vis-a-vis size of their installed capacity. There is an urgent need to take steps to include SHPs having an installed capacity of above 10 MW into the ambit of environment clearance process which is absent in many countries of the world at present.

Abstract It is usual to extract hot water from a storage tank, using displacement by cold water from the mains; this causes the temperature of the outgoing hot water to decrease with time. In order to alleviate this undesirable feature a number of tanks in series may be employed. In this communication the effect of number of tanks on the outlet temperature of hot water, has been analytically investigated; it has been assumed that the only heat exchange, taking place in the tanks is on account of flow of water. The considerations in this analysis are similar to those made by Rabinovich and Fert [1] and Rabinovich [2], for a system of tanks in a solar collector loop without any outflow of water. Thus the analysis is best applicable when hot water is extracted at a fast rate, so that the gain or loss of heat by other mechanisms is negligible, compared to that due to the flow of water. The analysis should also be applicable to shallow solar ponds, Sodha et al. [3], and built in storage water heaters, Sodha et al. [4].

Abstract The diesel engine is being widely used in day to day life in both mobile and stationary applications. The main drawback is the release of harmful gasses like HC, CO, NOx and particulate matter into the atmosphere. This affects both human beings and environment to a great extent and should be controlled effectively. This paper reviews the works on the control of diesel particulate matter in both pre-combustion and post-combustion techniques employed in the past few decades. The initial part of this review will discuss particulate matter composition and its structure. Then the various physical processes involved in the formation of particulate matter are discussed. Effects of fuel composition and its structure on soot formation are reported. Hazardous effects of particulate matter on both human beings and the environment are reviewed. Use of biodiesel water emulsified fuel as a fuel to control soot formation is highlighted. This review also highlights control of particulate matter by varying injection parameters like injection pressure, injection timing and auxiliary air injection. Multiple fuel injections within the same cycle to control NOx and particulate matter are also discussed. The conventional control technique of particulate matter by using Diesel particulate filter and its types are also compared with the new technologies. Various regeneration concepts to burn the collected soot are also highlighted. The major part of this review focuses on pre-combustion techniques to control particulate matter. This review paper, it is hoped, will be very useful for the researchers working on the control of diesel particulate matter.

Abstract Plastics have been reported as one of the major pollutants among various pollutants that are disposed of in the environment. They play a pivotal part in human life as they are cost-effective and are versatile. Plastics are known to have a mixture of many chemical components and are used for various domestic applications. Despite various useful applications, plastics take a long time to degrade. The burning of plastics releases chemicals such as phosgene and dioxides that are considered a hazard to the ecosystem. The toxic debris that is released from the plastics enters the food chain and water bodies in the form of microplastics. Microplastic-polluted foods and the presence of meager amounts of phthalates in toys lead to serious health consequences such as congenital diseases and malignant cancers. The dioxins released from the plastic polymers are lethally persistent organic pollutants which cause tumor and neurological damage in humans. Inadequate waste management practices have led to significant plastic pollution of water bodies. Plastics tend to settle on beaches, which decreases esthetic and recreation values. In this article, we have discussed ways for resource recovery from plastic wastes and the possible effects of plastics on the environment and available safety regulations for the use of plastics. This article also discusses scientific literature about the remediation of plastics using various methods, which can help to promote further improvement of the existing system by competent authorities and researchers.

Binary and ternary systems of Ni(2+), Zn(2+), and Pb(2+) were investigated at initial metal concentrations of 0.5, 1.0 and 2.0mM as competitive adsorbates using Arthrospira platensis and Chlorella vulgaris as biosorbents. The experimental results were evaluated in terms of equilibrium sorption capacity and metal removal efficiency and fitted to the multi-component Langmuir and Freundlich isotherms. The pseudo second order model of Ho and McKay described well the adsorption kinetics, and the FT-IR spectroscopy confirmed metal binding to both biomasses. Ni(2+) and Zn(2+) interference on Pb(2+) sorption was lower than the contrary, likely due to biosorbent preference to Pb. In general, the higher the total initial metal concentration, the lower the adsorption capacity. The results of this study demonstrated that dry biomass of C. vulgaris behaved as better biosorbent than A. platensis and suggest its use as an effective alternative sorbent for metal removal from wastewater.