Waste Soot Research Articles

Experimental comparison of the photothermal conversion performance of coal and plant soot nanofluids for direct absorption solar collectors

Direct absorption solar collectors (DASCs) based on nanofluids improve the thermal utilization efficiency of solar energy. In this study, the waste soot materials obtained from coal and plant biomass combustion were recycled. Deionized water was used as the basic fluid. A two-stage method was used to prepare coal soot (CS) and plant soot (PS) nanofluids. Detailed investigations and comparisons of the thermal conductivity and light-absorbing characteristics of the two fluids were performed. The results suggested that the introduction of soot nanoparticles improved the heat transfer and light-absorbing capacities of the base fluid and both thermal conductivity and optical absorption of soot nanofluids were positively correlated with the soot nanoparticle loading. Subsequently, photothermal conversion experiments were conducted internally and externally. The experimental results indicated that the PS nanofluids could absorb incident light radiation more efficiently and converted it into thermal energy. Specifically, the overall photothermal conversion efficiency of the PS nanofluid at a maximum mass fraction of 0.02% in the solar simulator was 55.7%, which was approximately 9.8% higher than that of the CS nanofluid. In addition, 42.3 °C and 44 °C were the maximum temperature increases under natural sunlight for the CS nanofluid and PS nanofluid, respectively. Notably, the waste soot materials are low cost and easily available. Therefore, this work demonstrates that recycled soot nanofluids, especially PS nanofluids, are promising candidates for application in DASCs systems.

Advances on value-added application of waste soot materials

In recent years, sustainable management has become the focus of research throughout the world. The present study is undertaken on the same line, that is, to address the potential applications of waste soot in various fields. Reuse/recycle of waste soot will reduce the health and environmental problems, and will lead to cleaner and greener earth; and also, will offer value-added products for various possible applications. In the present review, the potential sources of soot, its collection, refinement and utilization in various fields are addressed. The quality and application of waste soot depend on its carbon content. To the best of our knowledge, the present information will be useful to the business visionaries/researchers to develop suitable processes for mitigating the global problems associated with waste generation and its emissions into the atmosphere, and also to develop value-added products from the waste soot.

Multifunctional superhydrophobic adsorbents by mixed-dimensional particles assembly for polymorphic and highly efficient oil-water separation

Supra-wetting materials, especially superhydrophobic absorption materials, as an emerging advanced oil-water separation material have attracted extensive concern in the treatment of oil spillage and industrial oily wastewater. However, it is still a challenge to fabricate robust and multifunctional superhydrophobic materials for the multitasking oil-water separation and fast clean-up of the viscous crude oil by an environment-friendly and scalable method. Herein, a solid-solid phase ball-milling strategy without chemical reagent-free modification was proposed to construct heterogeneous superhydrophobic composites by using waste soot as the solid-phase superhydrophobic modifier. A series of covalent bond restricted soot-graphene (S-GN) or soot-Fe3O4 (S-Fe3O4) composite materials with a peculiar micro-nano structure are prepared. Through "glue+superhydrophobic particles" method, the prepared soot-based composite particles are facilely loaded on the porous skeleton of the sponge to obtain multifunctional superhydrophobic adsorbents. The reported superhydrophobic adsorbents exhibited robust chemical and mechanical stability, convenient magnetic collection, the high oil absorption capacity of 60–142 g g−1, durable recyclability (>250 cycles), efficient separation efficiency (>99.5%) and outstanding self-heated performance, which enable them to be competent for oil-water separation in multitasking and complex environment (floating oils, continuous oil collection, oil-in-water emulsion, and viscous oil-spills).

Fluorescent Carbon Dots Derived from Vehicle Exhaust Soot and Sensing of Tartrazine in Soft Drinks.

Recycling of waste into valuable products plays a significant role in sustainable development. Herein, we report the conversion of vehicle exhaust waste soot into water-soluble fluorescent carbon dots via a simple acid refluxion method. The obtained carbon dots were characterized using microscopic and spectroscopic techniques. Microscopic techniques reveal that the prepared carbon material is spherical in shape with an average particle size of ∼4 nm. Spectroscopic studies exhibited that the carbon dots are emissive in nature, and the emission is excitation-dependent. Further, the prepared carbon dots were successfully utilized as a fluorescent probe for the detection of tartrazine with a limit of detection of 26 nM. The sensitivity of carbon dots has also been realized by the detection of trace amounts of tartrazine in commercial soft drinks. Overall, this work demonstrates the conversion air pollutant soot into value-added fluorescent nanomaterials toward sensing applications.

Optimization of dye removal by diesel exhaust emission soot using response surface methodology

AbstractThe waste soot particles emitted from a diesel engine were studied as a dye adsorbent for water treatment. The input parameters were optimized using response surface methodology to achieve the maximum removal of dye methylene blue (MB). Experiments were conducted according to three‐level Box–Behnken Design with three factors time, pH, and initial concentration of dye in the solution. Further, analysis of variance analysis was carried out to find the level of significance of each parameter toward dye removal. Finally, for 0.05 g of diesel soot in a 50 ml solution, the maximum dye removal predicted was more than 99%. The basic medium (pH 12) found was favorable for the adsorption of MB. Also, 96% of detergent was removed in 60 min. Langmuir isotherm model and Pseudo‐second‐order kinetic model were most suitable for equilibrium and kinetic studies, respectively, for the removal of MB on diesel exhaust emission soot.

Conversion of Black Carbon Emitted from Diesel-Powered Merchant Ships to Novel Conductive Carbon Black as Anodic Material for Lithium Ion Batteries.

Waste soot generated from diesel engine of merchant ships has ≥ 2 µm agglomerates consisting of 30–50 nm spherical particles, whose morphology is identical to that of carbon black (CB) used in many industrial applications. In this study, we crystallized waste soot by heat treatment to transform it into a unique completely graphitic nano-onion structure, which is considerably different from that of commercial conductive CB. While commercial CB has a large specific surface area because of many surface micropores generated due to quenching by water-spraying in the production process, the heat-treated waste soot has a smooth micropore-free surface. Thus, the treated waste soot acquires the shape of CB but has a much smaller specific surface area. When the treated soot is used as a conductive material in lithium ion battery (LIB) half cells, the Coulombic efficiency of the entire anode is improved significantly owing to its low specific surface area; the electrochemical performance of the LIB is considerably enhanced compared to that of conventional conductive materials. Thus, polluting soot generated in marine propulsion can be transformed into a new class of CB with a unique structure by simple heat treatment; this soot can also be used as an inexpensive conductive material to enhance the LIB performance.

Diesel exhaust emission soot adsorbent for the removal of dye from wastewater

Diesel exhaust emission soot (DEES) is waste soot particle that has been explored as an adsorbent for a dye rhodamine B (RB). DEES successfully adsorbed the RB from its aqueous solution. Equilibrium was achieved in 90 min. Basic medium (pH > 7) was more favorable than an acidic medium for the adsorption of RB. The study of kinetic of adsorption reveals that both pseudo-first-order and second-order kinetic models fit well to kinetic data of adsorption. Langmuir isotherm best explains the equilibrium study of adsorption. The values of various kinetic and isotherm constants of DEES are compared with that of candle soot, and it is found that DEES is slightly superior to candle soot as an adsorbent. Further, DEES was coated on a polyurethane foam and adsorption–desorption experiments were performed. Also, DEES-coated foam (DEES foam) was successfully reused for six cycles after desorption in ethanol.

Utilization of Petroleum Coke Soot as Energy Storage Material

Anode active materials for lithium ion batteries (LIBs) were produced by using waste soot generated after combustion in a plant using petroleum coke as fuel. The soot collected from the boilers in the plant was graphitized through annealing, and this annealed soot was applied to anode active materials. After annealing at 2700 °C, the soot was converted into highly crystalline graphite with ring shapes approximately 100 nm in diameter. The lithium ion coin cells produced using graphitized soot showed high discharge capacity and excellent life cycle with a reversible capacity of 250 mAh/g even after 300 cycles at a rate of 1 C. This study describes a new possibility of using environmentally harmful combustion wastes of petroleum coke as a low-price anode material for LIBs by converting them into a graphite multilayer structure with a unique ring shape through annealing.

Recycling Waste Soot from Merchant Ships to Produce Anode Materials for Rechargeable Lithium-Ion Batteries

In this study, the waste soot generated by ships was recycled to produce an active material for use in lithium-ion batteries (LIBs). Soot collected from a ship was graphitized by a heat treatment process and used as an anode active material. It was confirmed that the graphitized soot was converted into a highly crystalline graphite, and was found to form carbon nano-onions with an average diameter of 70 nm. The graphitized soot showed a high discharge capacity and an excellent cycle life, with a reversible capacity of 260 mAhg−1 even after 150 cycles at a rate of 1 C. This study demonstrates that the annealed soot with a unique graphitic multilayer structure has an electrochemical performance that renders it suitable as a candidate for the production of low-cost anode materials for use in LIBs.

Morphological study of fluorescent carbon Nanoparticles (F-CNPs) from ground coffee waste soot oxidation by diluted acid

Coffee ground waste utilization for fluorescent carbon nanoparticles (F-CNPs) through soot oxidation with diluted HNO3 has been conducted. Soot was obtained through three different treatments to coffee ground waste; which was burned in furnaceat 550°C and 650°C and directly burned in a heat-proofcontainer. Then they were analyzed morphologically with Scanning Electron Microscope (SEM) instrument. Soot from direct burning indicated the optimum result where it has denser pores compared to other two soots. Soot obtained from direct burning was refluxed in diluted HNO3 for 12 hours to perform the oxidation. Yellowish brown supernatant was later observed which lead to green fluorescent under the UV light. F-CNPs characterization was done in Transmission Electron Microscopy, which showed that 7.4-23.4 nm of particle size were distributed.

Does foreign direct investment affect environmental pollution in China's cities? A spatial econometric perspective

Environmental pollution has aroused extensive concern worldwide. Existing literature on the relationship between foreign direct investment (FDI) and environmental pollution has, however, seldom taken into account spatial effects. Addressing this gap, this paper investigated the spatial agglomeration effects and dynamics at work in FDI and environmental pollution (namely, in waste soot and dust, sulfur dioxide, and wastewater) in 285 Chinese cities during the period 2003–2014, using global and local measures of spatial autocorrelation. Our results showed significant spatial autocorrelation in FDI and environmental pollution levels, both of which demonstrated obvious path dependence characteristics in their geographical distribution. A range of agglomeration regions were observed. The high-value and low-value agglomeration areas of FDI were not fully consistent with those of environmental pollution. This result indicates that higher inflows of FDI did not necessarily lead to greater environmental pollution from a geographic perspective, and vice versa. Spatial panel data models were further adopted to explore the impact of FDI on environmental pollution. The results of a spatial lag model (SLM) and a spatial error model (SEM) revealed that the inflow of FDI had distinct effects on different environmental pollutants, thereby confirming the Pollution Heaven Hypothesis and Pollution Halo Hypothesis. The inflow of FDI was found to have reduced waste soot and dust pollution to a certain extent, while it increased the degree of wastewater and sulfur dioxide pollution. The findings set out in this paper hold significant implications for Chinese environmental pollution protection.

선박용 디젤 엔진에서 생성된 폐 수트의 재활용에 관한 연구

선박용 디젤 엔진에서 생성된 폐 수트의 재활용에 관한 연구

Impact of waste soot on properties of coal-water suspensions

The study was conducted in order to implement the principles of Clean Production (CP) in the production of coal-water fuel. Promoting environmentally friendly technologies impact on the reduction of systemic waste, emissions and inputs, which in turn is beneficial to the environment, health and social security. Coal-water suspensions can be a substitute for fuel oil, which from an ecological point of view, is very advantageous with respect to reduced emissions of CO2, SO2 and NOx during the combustion of fuel. To improve the rheological properties of coal-water suspensions, various kinds of additives are used. Coal materials that belong to different assortments: jaret and fine coal and waste soot were used to prepare stable coal-water suspensions. The tests were performed on a laboratory scale in a disc mill. On the basis of the results, the most favourable parameters of process have been chosen (type of raw material and additive content and grinding time). The resulting suspensions are characterised by low viscosity and density, small equivalent diameters and high stability. Gas analysis of burning process of coal-water suspensions with (and without) soot (determination of O2, CO, NO, NO2, SO2, H2S, H2, CH4 and CO2) were conducted and compared.

A proposal of quantitative analysis method of emission characteristics of biodiesel fuel in diesel engine

In this study, the exhaust characteristics of the diesel engine for the change of the mixing ratio of biodiesel fuel were quantitatively analyzed by using the numerical analysis method. As the fuel in the experiment, the diesel and biodiesel (waste cooking oil, soybean oil), mixture BD2 (diesel only), BD3, BD5, BD20, BD50 and BD100 were used. The injection pressure (pinj) was set at 400 bar, 600 bar, 800 bar, 1000 bar and 1200 bar as the experimental variables. The concept of the standard deviation, Pearson’s correlation coefficient and Spearman rank-order correlation coefficient based on the statistics were introduced in order to analyze the exhaust characteristics of the quantitative NOx and Soot according to the injection pressure and the mixing ratio of biodiesel blended fuel. The regression method was introduced in order to obtain the increasing and decreasing aspects of NOx and Soot that can not be known from the correlation coefficients alone. From the study it is inferred that, for the waste cooking oil, NOx and Soot can be simultaneously reduced through control of the mixing ratio in the region of pinj=400 bar and pinj=600 bar, and the Soot can be reduced without affecting the emission of NOx for pinj more than 800 bar. For the soybean oil, NOx and Soot can be simultaneously reduced at pinj=400 bar and the Soot can be reduced without affecting the emission of NOx at pinj=600 bar.

Preparation of Single-Walled Carbon Nanotubes from Fullerene Waste Soot

Single-walled carbon nanotubes (SWCNTs) were successfully prepared from fullerene waste soot (FWS) by the arc discharge method in a helium atmosphere. The yield of the as-prepared SWCNTs reached as high as 6 g/h, indicating a great potential for further large scale production. FWS-based SWCNTs were systematically examined using scanning electron microscopy, transmission electron microscope, high-resolution transmission electron microscopy, and Raman spectroscopy. The results show that the as-obtained SWCNTs have an extraordinary crystalline integrity with a diameter of 1.2–2.2 nm. Compared with the SWCNTs synthesized from graphite under the same experimental conditions, it was found that FWS as feedstock for synthesis of SWCNTs was more efficient due to its higher reactivity in the electric arc discharge environment. The possible mechanism involved in the formation process of SWCNTs from FWS is proposed and discussed in terms of its turbostratic structure with pentagonal defects and the process parameters...

Feasibility of Fullerene Waste as Carbonaceous Adsorbent

This note investigates using the waste soot generated in fullerene manufacture as an adsorbent. Both oven-dried and air-activated samples of waste soot are compared with three commercially available powdered activated carbons (PACs): Nuchar-SA, HDH, and Calgon-RC. Three model compounds were chosen for adsorption tests--TCE, Benzene, and Phenol--representing a small branched molecule, a small nonpolar ring molecule, and relatively polar ring molecule. Additionally, the effectiveness of total organic carbon (TOC) removal from wastewater was evaluated. Oven-dried soot performed poorly as compared to the commercial carbons, but activation of the waste soot for 60 min at 450 C in air resulted in an activated carbon (aFWS) with properties similar to those of commercially available PACs. The aFWS performed better than one would predict from the typical characterization measures of iodine number, molasses number, and methylene blue number. The data for phenol suggest some functional groups are created during the activation of the waste soot. These results show that large-scale fullerene manufacturing can be a zero-waste industry, because its primary waste product can be converted into a useful material.