In this study poly (4-nitrophenylazo-3-aminopyridine - formaldehyde) (PNAAP-F) and poly (4-nitroarylazo-3-chloro-6-hydroxypyridine - formaldehyde) (NAACHP-F) were synthesized via diazotization, coupling and polycondensation reactions. The structural properties of the as-synthesized dyes were acquired using Fourier-transform infrared spectroscopy (FTIR) and UV-visible absorption maxima and their color, yield, melting point, solubility, and viscosity were determined via standard methods. UV-visible and FTIR results show successful formation of the polymeric dyes due to shift of wavelength of maximum absorption (λmax) (440-490 nm, 480-540 nm) and new absorption peak at around (2780-2995 cm-1) for methylene bridge respectively. The dyes were found to be of good yield (monomeric: 73.3%-87.2 %, polymeric: 53.8%-76.6 %), low melting point (monomeric: 112.6-121.2, and 136.0-137.0 °C, while polymeric: 134.0-144.5, and 149.4-154.7 °C), soluble in some solvents. The dyeing activity was carried out and assessed on nylon and polyester fabrics using the standard methods. The dyeing process was carried out via high temperature and carrier dyeing methods. The dyeing properties of the synthesized dyes were compared with those of commercial disperse dyes (terasil brilliant violet and terasil scarlet, brown). The dyeings of nylon and polyester had a very attractive hue and the color ranges from yellow and deep yellow shades with very good to excellent fastness to light, washing, hot pressing, and rubbing.
Agro-industrial biorefinery effluent (AIBW) is considered a highly polluting source responsible for environmental contamination. It contains high loads of chemical oxygen demand (COD), and phenol, with several other organic and inorganic constituents. Thus, an economic treatment approach is required for the sustainable discharge of the effluent. The long-term process performance, contaminant removal and microbial response of AIBW to rice straw-based biochar (RSB) and biochar-based geopolymer nanocomposite (BGC) as biosorbents in an activated sludge process were investigated. The adsorbents operated in an extended aeration system with a varied hydraulic retention time of between 0.5 and 1.5 d and an AIBW concentration of 40-100% for COD and phenol removal under standard conditions. Response surface methodology was utilised to optimize the process variables of the bioreactor system. Process results indicated a significant reduction of COD (79.51%, 98.01%) and phenol (61.94%, 74.44%) for BEAS and GEAS bioreactors respectively, at 1 d HRT and AIBW of 70%. Kinetic model analysis indicated that the Stover-Kincannon model best describes the system functionality, while the Grau model was better in predicting substrate removal rate and both with a precision of between R2 (0.9008-0.9988). Microbial communities examined indicated the abundance of genera, following the biosorbent addition, while RSB and BGC had no negative effect on the bioreactor's performance and bacterial community structure of biomass. Proteobacteria and Bacteroidetes were abundant in BEAS. While the GEAS achieved higher COD and phenol removal due to high Nitrosomonas, Nitrospira, Comamonas, Methanomethylovorans and Acinetobacter abundance in the activated sludge. Thus, this study demonstrated that the combination of biosorption and activated sludge processes could be promising, highly efficient, and most economical for AIBW treatment, without jeopardising the elimination of pollutants or the development of microbial communities.
Several agro-waste materials have been utilized for sustainable engineering and environmental application over the past decades, showing different degrees of effectiveness. However, information concerning the wider use of palm oil clinker (POC) and its performance is still lacking. Therefore, as a solid waste byproduct produced in one of the oil palm processing stages, generating a huge quantity of waste mostly dumped into the landfill, the waste-to-resource potential of POC should be thoroughly discussed in a review. Thus, this paper provides a systematic review of the current research articles on the several advances made from 2005 to 2021 regarding palm oil clinker physical properties and performances, with a particular emphasis on their commitments to cost savings during environmental and engineering applications. The review begins by identifying the potential of POC application in conventional and geopolymer structural elements such as beams, slabs, and columns made of concrete, mortar, or paste for coarse aggregates, sand, and cement replacement. Aspects such as performance of POC in wastewater treatment processes, fine aggregate and cement replacement in asphaltic and bituminous mixtures during highway construction, a bio-filler in coatings for steel manufacturing processes, and a catalyst during energy generation are also discussed. This review further describes the effectiveness of POC in soil stabilization and the effect of POC pretreatment for performance enhancement. The present review can inspire researchers to find research gaps that will aid the sustainable use of agroindustry wastes. The fundamental knowledge contained in this review can also serve as a wake-up call for researchers that will motivate them to explore the high potential of utilizing POC for greater environmental benefits associated with less cost when compared with conventional materials.
The high nutrient concentration in domestic wastewater effluent can endanger the aquatic life via eutrophication. Thus, research have been carried out to prevent harm to aquatic life. In regard biofilm reactors have been successful by far with few limitations. Bio-carrier fabrication of desired shape is one of the limitations. Recently, the invention of additive manufacturing (AM) of object made it feasible to fabricate the desired shape. In this study additive manufactured bio‒carrier (AMB) was printed using AM technique, with high surface area to volume ratio as well as density higher than water. The submerged attach growth sequencing batch biofilm reactor (SAGSBBR) for organic and nutrient removal from domestic wastewater (DWW) was conducted to determine the optimum bio‒carrier filling ratio (FR) and cycle time (CT) by using response surface methodology (RSM) with CT ranging between 12 h and 24 h and FR ranging between 0 and 20%. The maximum chemical oxygen demand (COD), ammonia-nitrogen (NH4 +‒N), and total phosphorus (TP) removal was 96.8 mg/L, 93.32 mg/L, and 88.89 mg/L respectively, which was achieved in submerged attached growth sequential biofilm batch reactor with 10% FR (SAGSBBR‒10). The optimization study determined the optimal solution of CT and FR to be 17.07 h and 12.38% respectively, with desirability of 0.987. The predicted mean of responses for the optimal solution were 96.64%, 94.40% and 89.94% for COD removal, NH4 +‒N removal and TP removal, respectively. The rate of biomass attachment at the first stage in SAGSBBR‒10 and SAGSBBR‒20 was about 11.39 mg/carrier.d and 8.64 mg/carrier.d, whereas the highest accumulation achieved was 98.27 mg/carrier and 80.15 mg/carrier respectively. Thus, this study can assist us to achieve sustainable development goal (SDG) 6.