High surface area and mesoporous activated carbon from KOH-activated dragon fruit peels for methylene blue dye adsorption:Optimization and mechanism study

In this study,an alternative precursor for production of activated carbon was introduced using dragon fruit(Hylocereus costaricensis)peel(DFP).Moreover,KOH was used as a chemical activator in the thermal carbonization process to convert DFP into activated carbon(DFPAC).In order to accomplish this research,several approaches were employed to examine the elemental composition,surface properties,amorphous and crystalline nature,essential active group,and surface morphology of the DFPAC.The BrunauerEmmettTeller test demonstrated a mesoporous structure of the DFPAC has a high surface area of 756.3 m2g 1.The cationic dye Methylene Blue(MB)was used as a probe to assess the efficiency of DFPAC towards the removal of MB dye from aqueous solution.The effects of adsorption input factors(e.g.DFPAC dose(A:0.040.12 g L 1),pH(B:310),and temperature(C:3050℃))were investigated and optimized using statistical analysis(i.e.BoxBehnken design(BBD)).The adsorption kinetic model can be best categorized as the pseudofirst order(PFO).Whereas,the adsorption isotherm model can be best described by Langmuir model,with maximum adsorption capacity of DFPAC for MB dye was 195.2 mg g 1 at 50℃.The adsorption mechanism of MB by DFPAC surface was attributed to the electrostatic interaction,pp interaction,and Hbonding.Finally,the results support the ability of DFP to be a promising precursor for production of highly porous activated carbon suitable for removal of cationic dyes(e.g.MB).

Adsorption Isotherm Study of Activated Fruit Peels for Copper Removal

Heavy metal polluted water threatens the integrity of ecosystem.The use of agricultural waste as adsorbent becomes popular due to its biodegradability and availability.However,limited research works has been done to process agricultural waste for heavy metal adsorption purpose.The objective of this study is to propose a new approach to treat banana peel using ZnCl_(2) prior to alkali and acid treatment and explore the potential of dragon fruit peels as the adsorbent for Cu^(2+)adsorption.Seven adsorption isotherm was adopted to identify the adsorption mechanism and four statistical parameters were calculated for model verification purpose.The experiment was conducted by dispersing ZnCl_(2) treated and untreated adsorbents into Cu^(2+) solution.Results showed that ZnCl_(2) treated adsorbents performed better in terms of Cu^(2+) removal compared with untreated adsorbents due to higher surface area for Cu^(2+) adsorption.The treated banana peel(Act.-B)performed approximately 30%better than the treated dragon fruit peel(Act.-D)due to the presence of hydroxyl and carboxyl groups.The equilibrium adsorptive capacity of Act.-B was 1872.8 mg Cu^(2+)/g and the experimental data fitted Freundlich isotherm well with R^(2)=0.9978,0.0161 of residual sum of error(SSE),0.0068 of χ^(2),and 0.0567 of root mean square error(RMSE)values.This suggests non⁃linear adsorption and multilayer adsorption on heterogenous surfaces.Thus,it is recommended to further improve the surface properties of Act.-B by steam pyrolysis and surface modification.

Insights into flavonoid biosynthesis during cucumber fruit peel coloration based on metabolite profiling and transcriptome analyses

The fruit peel color is a crucial trait of cucumber.To better understand the molecular mechanisms underlying cucumber peel coloration,we compared the UPLC-ESI-MS/MS-based flavonoid metabolomic and RNA sequencing-based transcriptomic profiling of the brown peeled cucumber line‘PW’at six developmental stages.A total of 210 flavonoid metabolites were identified.Of which,117 flavonoid metabolites were differentially accumulated.In this study,weighted gene co-expression network analysis combined with Kyoto Encyclopedia of Gene and Genomes enrichment analysis revealed key genes coding for seven enzymes and eight transcription factors(TFs)associated with flavonoid biosynthesis.Among them,the R2R3MYB CsaV3_4G001130 is the best candidate gene that is responsible for controlling mature fruit colors in cucumber.Sanger sequencing revealed one nonsynonymous SNP in the exon of CsaV3_4G001130 among the selected 11 cucumber lines,which introduced a premature stop codon,generating a truncated protein in pale yellow or creamy peeled fruits.Yeast two-hybrid assays showed a direct interaction of CsaV3_4G001130 with the bHLH TF CsaV3_1G002260 and the WD40 protein CsaV3_5G001800.However,the interactions were influenced by the nonsynonymous SNP we identified.Our finding revealed that the integrated transcriptome and metabolome analysis further demonstrated that the abundance of some pigmented flavonoids(especially anthocyanins and chalcones)contributed to the coloration of‘PW’fruits.These findings pave the way for elucidation of flavonoid biosynthesis and improvement of cucumber peel color in the future.

Phytonutrient pellet supplementation enhanced rumen fermentation efficiency and milk production of lactating Holstein-Friesian crossbred cows

The objective of this experiment was to investigate the effects of inclusion of dragon fruit peel pellet(DFPP) and dietary non-protein nitrogen (NPN) on nutrients digestibility, rumen fermentation efficiency,plasma antioxidant activity, microbial protein synthesis, milk yield and composition in lactatingHolstein-Friesian crossbred cows. Four animals were randomly allotted to 4 dietary treatments accordingto a 2 ×2 factorial arrangement in 4 ×4 Latin square design. The treatments were as follows: 300 g DMof DFPP t100 g of urea (T1), 300 g DM of DFPP t 200 g of urea (T2), 400 g DM of DFPP t 100 g of urea(T3), and 400 g DM of DFPP t 200 g of urea (T4), respectively. The results showed that intake of ricestraw was increased (P < 0.01) by the DFPP addition. Including DFPP and urea did not affect (P > 0.05) theNDF and ADF digestibilities, but increased the apparent digestibilities of dry matter, organic matter, andcrude protein (P < 0.01). Rumen fermentation process, especially the propionate concentration, wassignificantly increased by the DFPP levels. The plasma antioxidant activity was increased (P > 0.05) withthe addition of DFPP. The DFPP improved (P < 0.01) microbial protein synthesis. The supplementation ofDFPP and urea increased (P < 0.05) milk fat, whereas milk yield and 3.5% fat corrected milk were onlyincreased (P < 0.05) by the DFPP supplementation. Based on these results, addition of DFPP at 400 g/animal per day with urea at 100 g/animal per day improved rumen fermentation, plasma antioxidantactivity, milk yield and milk fat percentage.