Removal of diesel pollution by biochar - support in water remediation

Abstract

Water contaminated with diesel oil represents one of the greatest challenges in waste water management. Water soluble fraction (WSF) is of particular interest because of its toxicity to aquatic organisms and discharge regulations set by environmental authorities. Biochar sorbents have attracted great attention, due to their low cost origin and advantageous properties as well as high sorption capacities in sorption processes. In this study, we have reported the synthesis and characteristics of novel biochar sorbent made from waste lignocellulosic biomass (peach stones (PS)) and evaluated its possible application in removal of diesel WSF from synthetic water. Physiochemical characteristics of the biochar sample were analysed by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method, and Fourier-transform infrared spectroscopy (FTIR), along with the elemental analysis. Characterisation of PS biochar (PS-B) indicated high multi porous surface area (159.1 m2 g-1) with the average pore diameter 2.7 nm. FTIR results indicated higher presence of aromatic compounds in PS-B as compared to PS. The sorption experiments performed in a batch system using PS-B resulted in more than 95 % removal of diesel WSF, reaching equilibrium after 5 h. Equilibrium data were well fitted by Freundlich isotherm, while the pseudo-second order equation fitted well the kinetic data, indicating chemisorption involving valency forces through the sharing/exchange of electrons between the sorbent and PS-B. Applications of ecotoxicology tests based on a microbial biosensor (Aliivibrio fischeri) have shown a significant toxicity reduction of water sample after the treatment with biochar.

Efficient Removal of Water Soluble Fraction of Diesel Oil by Biochar Sorption Supported by Microbiological Degradation

“…The characteristics of the pyrolysis final product depend on feedstock composition and process parameters, especially applied temperatures. The decomposition process is followed by the release of volatile matter, and the obtained product plum stone biochar is presented with a decreased amount of H and O and with a higher C concentration [5]. As can be seen from Table 1, the content of C is higher in PmS-B obtained at 500 • C (71.78%) in comparison to the raw biomass (48.51%).…”

“…For the purpose of kinetic investigations, batch sorption experiments were performed by mixing 1.5 g of PmS-B in 100 mL of the synthetic DO solution (the initial WSF concentration was 18 mg/L). Erlenmeyer flasks (250 mL) with saturated DO solutions were placed in an orbital shaker (Heidolph Unimax 1010, Schwbach, Germany) and shaken for different time intervals (2,5,10,20,30,60, 90 and 120 min) at 25 • C at an agitation speed of 200 rpm; the pH value of the initial solution was 6.…”

“…Many methods have been created for the removal of high concentrations of insoluble, floating DO fraction; unfortunately, they are often inadequate to remove the low concentrations of dissolved DO contamination [4]. The composition and the concentration of the "water soluble fraction" (WSF) of DO depend upon several factors, e.g., DO composition, properties of the water, temperature and the preparation method [5]. The WSF consists of several toxic components such as PAHs, mono-aromatic hydrocarbons (benzene, toluene, ethylbenzene and xylenes), phenols and heterocyclic compounds and heavy metals [6].…”

“…For this purpose, different techniques might be used, but sorption and biological remediation are often seen as the most environmentally and economically advantageous choices. These techniques are cost-effective, relatively simple to execute, demonstrate high removal efficiencies, require minimal energy or chemical usage, and reduce the potential for secondary contamination [5].…”

“…This might promote the conversion of waste streams into useful resources using novel and sustainable methods and support the circular economy principles of reducing, reusing, and recycling waste materials [7]. Sorbents made of lignocellulosic waste biomass (LCW) originating from the food industry or agriculture hold particular significance because their application decreases the deposits of waste in landfills, diminishes greenhouse gas emissions, and offers a renewed value to the wasted products [5]. Unfortunately, direct application of raw biomass often suffers from its limited sorption capacity, low stability and associated secondary pollution generation, inducing the need for modification/conversion.…”