Alternative green application areas for olive pomace catalytic pyrolysis biochar obtained via marble sludge catalyst.

Evaluating industrial wastes in the system with minimum preprocessing and generation economically valuable products from them have critical importance. In this regard, especially cheap, wieldy, and readily available catalysts have been researched to increase variety of useful products in pyrolysis systems, to reduce process time, and to increase quality and diversity of products. Therefore, in this study, marble sludge (named K1) was evaluated as catalyst at different dosages (10%, 20%, 30%, 50%) and pyrolysis temperatures (300, 500, 700 °C) in olive pomace (OP) pyrolysis and; the potential green applications of produced new biochars at new usage areas with different purposes based on characteristics were investigated. ANOVA test results showed that temperature and catalysts ratio had significant effect on pyrolysis product yields since significance value for K1 and temperature was lower than 0.05 for pyrolysis products. OP-K1 biochars had alkaline properties and high earth metal quantities. Moreover, increment in K1 ratio and temperature resulted in decrement of the biochar surface acidity. Therefore, it can be indicated that these biochars can have a potential usage for anaerobic digestion processes, lithium-ion batteries, and direct carbon solid oxide fuel cell (DC-SOFC) but further electrochemical property test should be performed. Moreover, produced biochars can be alternative fuels in some processes instead of coal since they have low S content and high heat values. Consequently, it is foreseen that produced biochars will have an important place in the development of potential usage areas with a new and environmentally friendly approach in different areas apart from the conventional uses of catalytic pyrolysis chars.

Co-flotation of effluents from detergent and marble processing industries in Denver and dispersed air flotation systems.

Suspended solids in the marble processing wastewater (MPWW) have the potential to pollute receiving media. Likewise, detergent production wastewater (DPWW) needs treatment prior to discharge as they include surfactants and others. Flotation and its modifications are common for separation purposes in various engineering solutions. To increase flotation performance by changing the surface tension some collector and frother chemicals, surfactants are utilized. Detergents are among important surfactants and they may act as both frother and collector in flotation. Therefore, the purpose of this study was to determine the effectiveness of DPWW in co-flotation with MPWW. Two effluents were mixed at varying ratios and dispersed air (DISP) and Denver (DEN) flotation co-treatment were applied to the mixtures. Volume ratio, time and air flow rate on treatment performance were investigated. Turbidity, solids, COD, phosphate removals were achieved at varying levels when the flotation was applied to the mixture. The highest treatment performance was achieved at 90%MPWW-10%DPWW mixture. 10 min flotation time and 2 L min-1 air flow rate for the DEN system, and 20 min and 6 L min-1 for the DISP system were recommended. Under these conditions turbidity, SS, COD, phosphate and alkalinity residuals (and removal efficiencies) were 2400 NTU(82%), 1720 mg.L-1(89%), 313.6 mg.L-1(10%), 20 mg.L-1(20%) and 600 mg.L-1CaCO3(92%) in the DEN system, respectively. Whereas, in the DISP system, under the same conditions, final values of 1880 NTU(86%), 1540 mg.L-1(91%), 262 mg.L-1(17%), 21 mg.L-1(20%) and 470 mg.L-1(94%) were obtained, respectively. The highest SludgeSS concentration increased up to 19300 mg.L-1 in the 90%-10% mixture. In all samples, dewaterable sludge was obtained. By this study, co-flotation of these two effluents was recommended. Within SDGs, this approach will replace frother chemical usage. The process performance can further be enhanced via flotation modifications and technology can be developed as further study.

The role of physicochemical marble processing wastewater treatment sludge in the production of new generation pyrolysis char from waste polypropylene.

The effects of marble processing wastewater physicochemical treatment sludge (K1) on polypropylene (PP) waste pyrolysis were investigated by lab-scale batch pyrolysis system. PP-K1 proportions and pyrolysis temperature were studied as variables and both were found to have influences onto pyrolysis char, oil/tar, gas fractions distribution, as well as pyrolysis char characteristics (determined via SEM, EDX, FTIR, TGA and XRD analyses). The influence of K1 could be related to its high mineral composition (CaCO3, CaMg(CO3)2 and (Mg0.03Ca0.97)(CO3)) which also detected in the char products. K1 acts as catalyst and remained unchanged in thermochemical reactions below 700°C. The main thermal degradation of PP occurs around 400-470°C, although it starts at about 300-350°C, whereas, K1 resulted in more thermal degradation at 300°C pyrolysis. As K1 dose increased, pyrolysis chars became more thermally stable with the pyrolysis temperature. Diverse types of chars in terms of porosity, thermal strength and chemical structure were produced with PP + K1 as compared to the PP chars. For example, with 10%-20% K1 doses, the chars are in aromatic structure while chars become aliphatic when K1 dosage increased to 30% or above. The structural diversity made these chars new products that can be used as raw material for subsequent purposes. This study provided a basis for the chars' physical and chemical properties which are needed for further research to develop new generation evaluation areas for them. Therefore, a new symbiotic upcycling approach has been presented for PP wastes and marble processing wastewater treatment sludge.