Removal of methylene blue from water by food industry by-products and biochars

Orfanos, Alexios G.; Manariotis, Ioannis D.; Karapanagioti, Hrissi K.

doi:10.5004/dwt.2018.21999

Cited by 11 publications

(14 citation statements)

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“…This is due to the low pyrolysis temperature which is not high enough to decompose significantly the organic phase. Studies showed that only biochars prepared at high pyrolysis temperatures can have a significant amount of micropores 24,34 . On the other hand, this is beneficial for maintaining the shape and the dimensions of kernels and their strength too.…”

Section: Resultsmentioning

confidence: 99%

Chlorococcum sp. biofilm growth on biochar from olive kernels solid support

Tsavatopoulou

Vakros

Manariotis

2023

J of Chemical Tech & Biotech

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BACKGROUND: Biofilm is a complex community of microorganisms including microalgae, bacteria and protozoa, which are adhered to a surface. The purpose of an integrated microalgal processing system is the production of biofuels, biomass and other valuable bioproducts as well as wastewater remediation. Biochar is a carbon-rich and porous substrate, capable of adsorbing nutrients.RESULTS: In this study, biochar produced from olive kernels pyrolyzed at 400 °C was tested as a solid support candidate for adhering Chlorococcum sp. cultures. The substrate used was BG-11 with 1/3 nitrates and BG-11 without nitrates and phosphates. After 15 days of cultivation, the biomass attached to biofilm was measured, while different parameters were determined in the liquid. Among the different concentrations of biochar used, the culture containing 1 g L −1 biochar gave the best performance, resulting in 1.28 and 1.24 g microalgae g −1 biochar in the presence and absence of nitrates, respectively. CONCLUSION: The cultures containing BG-11 without nitrogen and phosphorus showed leaching of nutrients in the liquid of the reactor. The present findings provide an alternative use of biochar, enhancing the growth of microalgae, and thus encouraging its use as supporting material in bioreactors.

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Section: Resultsmentioning

confidence: 99%

Chlorococcum sp. biofilm growth on biochar from olive kernels solid support

Tsavatopoulou

Vakros

Manariotis

2023

J of Chemical Tech & Biotech

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“…However, nitrate removal was not affected by the modification but only by the temperature. transfer, while if the plot is nonlinear or linear but does not pass through the origi film diffusion or chemical reaction control the sorption rate [17,50]. The Boyd plot s multi-linearity over the time period studied (Figure 5), without passing through the o for the majority of the materials examined, thus rendering it quite difficult to p whether external mass transfer or intra-particle diffusion is the rate controlling step.…”

Section: Effect Of Contact Time On Sorption Processmentioning

confidence: 98%

“…The diffusion of nutrients by the Weber-Morris model is shown in Figure 4. If the plot of q with t 1/2 provides a straight line, an intra particle diffusion is involved in the sorption rate and, if the straight line cross the origin, intraparticle diffusion is the rate limiting step [17]. In most cases, two or three linear parts were observed, which implies that different mechanisms are involved in the sorption process.…”

Section: Effect Of Contact Time On Sorption Processmentioning

confidence: 99%

“…To estimate the actual rate-limiting step involved in the sorption process, the experimental data were further analyzed by the Boyd model. If the plot of Bt against time is linear and passes through the origin, the intraparticle diffusion controls the rate of mass transfer, while if the plot is nonlinear or linear but does not pass through the origin, the film diffusion or chemical reaction control the sorption rate [17,50]. The Boyd plot shows multi-linearity over the time period studied (Figure 5), without passing through the origin for the majority of the materials examined, thus rendering it quite difficult to predict whether external mass transfer or intra-particle diffusion is the rate controlling step.…”

Section: Effect Of Contact Time On Sorption Processmentioning

confidence: 99%

“…Coffee is one of the most consumed beverages all over the world. In 2016, the production of coffee reached about 9 × 10 6 tonnes [17]. The carbon and oxygen in spent coffee grounds comprise almost 84% and 12% in an atomic ratio [18].…”

Section: Introductionmentioning

confidence: 99%

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Screening of Raw and Modified Biochars from Food Processing Wastes for the Removal of Phosphates, Nitrates, and Ammonia from Water

2022

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The aim of this work was to compare the performance of biochar from various food processing wastes of different origin for the removal of different nutrients from water. Eggshells (EGS), rice husk (RH), and coffee biochars were pyrolyzed at 400 and 800 °C and were examined for the removal of phosphates, nitrates, and ammonia nitrogen. The raw materials were also modified with magnesium chloride in order to investigate their sorption behavior. The highest sorption capacity (qmax) for phosphates and ammonium was observed with EGS pyrolyzed at 800 °C and was 11.45 mg PO43−-P/g and 11.59 mg NH3-N/g, while the highest nitrates sorption capacity was observed with the magnesium-modified RH pyrolyzed at 800 °C (5.24 mg NO3−-N). The modified EGS biochars pyrolyzed at 800 °C had almost the half the sorption capacity for phosphates and nitrates compared to the unmodified materials. The modification of RH pyrolyzed at 800 °C resulted in higher sorption capacity by 34 and 158% for phosphates and ammonium, respectively. The coffee raw and modified biochars were less efficient in nutrient removal compared to the other materials. The specific surface area values of the biochars examined is not a decisive factor for nutrient sorption. The reaction between magnesium and calcium (for the eggshell samples) ions with phosphates is responsible for the higher sorption efficiency. On the other hand, the presence of magnesium and calcium ions has a detrimental effect on the sorption of NH3-N.

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Lipid conversion of Scenedesmus rubescens biomass into biodiesel using biochar catalysts from malt spent rootlets

Tsavatopoulou

Vakros

Manariotis

2020

J of Chemical Tech & Biotech

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BACKGROUNDMicroalgae are considered a third–generation raw material for biofuel production. This work compared the conversion of the extracted oil from the freshwater microalgae Scenedesmus rubescens via transesterification for the production of biodiesel. Considering the cost of biodiesel production, heterogeneous catalysts present a significant advantage because of their stability and reusability. Biochar and modified biochar with H2SO4 were used as catalysts.RESULTSBiochar (BC) was pyrolyzed at 850 °C, under limited oxygen conditions, and was activated by sulphuric acid (H–BC). The catalyst: oil mass ratios tested were from 0 to 0.7:1 for BC, and from 0 to 1:1 for H–BC. The biochar sample exhibited a strong buffer capacity in the pH range between 7 and 5.5, while the acid treated biochar was strongly acidic and could neutralize a significant amount of bases. The produced methyl esters are almost the same in all cases examined. BC samples gave better transesterification results, as far as it concerns the conversion, compared to H–BC.CONCLUSIONThe enhanced activity of the BC with mass used may be correlated with the basic minerals presented on the biochar surface. Raw biochar gave better conversion results (47%) during transesterification compared to the modified biochar with H2SO4 (24%) with better catalyst to molar ratio, 0.7:1 and 0.1:1, respectively. © 2020 Society of Chemical Industry

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Removal of methylene blue from water by food industry by-products and biochars

Cited by 11 publications

References 0 publications

Chlorococcum sp. biofilm growth on biochar from olive kernels solid support

Chlorococcum sp. biofilm growth on biochar from olive kernels solid support

Screening of Raw and Modified Biochars from Food Processing Wastes for the Removal of Phosphates, Nitrates, and Ammonia from Water

Lipid conversion of Scenedesmus rubescens biomass into biodiesel using biochar catalysts from malt spent rootlets

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