Recovery of cellulose fibers from oil palm empty fruit bunch for pulp and paper using green delignification approach

The aim of this work was to recover the cellulose fibers from EFB using low-transition-temperature-mixtures (LTTMs) as a green delignification approach. The hydrogen bonding of LTTMs observed in 1H NMR tends to disrupt the three-dimensional structure of lignin and further remove the lignin from EFB. Delignification process of EFB strands and EFB powder were performed using standard l-malic acid and cactus malic acid-LTTMs. The recovered cactus malic acid-LTTMs showed higher glucose concentration of 8.07 mg/mL than the recovered l-malic acid LTTMs (4.15 mg/mL). This implies that cactus malic acid-LTTMs had higher delignification efficiency which led to higher amount of cellulose hydrolyzed into glucose. The cactus malic acid-LTTMs-delignified EFB was the most feasible fibers for making paper due to its lowest kappa number of 69.84. The LTTMs-delignified EFB has great potential to be used for making specialty papers in pulp and paper industry

Review of Adsorption Studies for Contaminant Removal from Wastewater Using Molecular Simulation

In recent years, simulation studies have emerged as valuable tools for understanding processes. In particular, molecular dynamic simulations hold great significance when it comes to the adsorption process. However, comprehensive studies on molecular simulations of adsorption processes using different adsorbents are scarcely available for wastewater treatment covering different contaminants and pollutants. Hence, in this review, we organized the available information on various aspects of the adsorption phenomenon that were realized using molecular simulations for a broad range of potentially effective adsorbents applied in the removal of contaminants from wastewater. This review was compiled for adsorbents under five major categories: (1) carbon-based, (2) oxides and hydroxides, (3) zeolites, (4) metal–organic frameworks and (5) clay. From the review, it was found that simulation studies help us understand various parameters such as binding energy, Gibbs free energy, electrostatic field, ultrasound waves and binding ability for adsorption. Moreover, from the review of recent simulation studies, the effect of ultrasound waves and the electrostatic field was elucidated, which promoted the adsorption capacity. This review can assist in the screening of classified adsorbents for wastewater treatment using a fast and cheap approach while helping us understand the adsorption process from an atomistic perspective

Production of biochar from rice straw and its application for wastewater remediation − An overview

The valorization of biochar as a green and low-cost adsorbent provides a sustainable alternative to commercial wastewater treatment technologies that are usually chemical intensive and expensive. This review presents an in-depth analysis focusing on the rice straw-derived biochar (RSB) for removal of various types of contaminants in wastewater remediation. Pyrolysis is to date the most established technology to produce biochar. Subsequently, biochar is upgraded via physical, chemical or hybrid activation/modification techniques to enhance its adsorption capacity and robustness. Thus far, acid-modified RSB is able to remove metal ions and organic compounds, while magnetic biochar and electrochemical deposition have emerged as potential biochar modification techniques. Besides, temperature and pH are the two main parameters that affect the efficiency of contaminants removal by RSB. Lastly, the limitations of RSB in wastewater remediation are elucidated based on the current advancements of the field, and future research directions are proposed

Progress in thermochemical co-processing of biomass and sludge for sustainable energy, value-added products and circular economy

To achieve the main goal of net zero carbon emission, the shift from conventional fossil-based energy/products to renewable and low carbon-based energy/products is necessary. Biomass has been perceived as a carbon–neutral source from which energy and value-added products can be derived, while sludge is a slurry waste that inherently contains high amount of minerals and organic matters. Hence, thermochemical co-processing of biomass wastes and sludge could create positive synergistic effects, resulting in enhanced performance of the process (higher conversion or yield) and improved qualities or characteristics of the products as compared to that of mono-processing. This review presents the current progress and development for various thermochemical techniques of biomass-sludge co-conversion to energy and high-value products, and the potential applications of these products from circular economy’s point of view. Also, these technologies are discussed from economic and environmental standpoints, and the outlook towards technology maturation and successful commercialization is laid out

A systematic review of the molecular simulation of hybrid membranes for performance enhancements and contaminant removals

Number of research on molecular simulation and design has emerged recently but there is currently a lack of review to present these studies in an organized manner to highlight the advances and feasibility. This paper aims to review the development, structural, physical properties and separation performance of hybrid membranes using molecular simulation approach. The hybrid membranes under review include ionic liquid membrane, mixed matrix membrane, and functionalized hybrid membrane for understanding of the transport mechanism of molecules through the different structures. The understanding of molecular interactions, and alteration of pore sizes and transport channels at atomistic level post incorporation of different components in hybrid membranes posing impact to the selective transport of desired molecules are also covered. Incorporation of molecular simulation of hybrid membrane in related fields such as carbon dioxide (CO2) removal, wastewater treatment, and desalination are also reviewed. Despite the limitations of current molecular simulation methodologies, i.e., not being able to simulate the membrane operation at the actual macroscale in processing plants, it is still able to demonstrate promising results in capturing molecule behaviours of penetrants and membranes at full atomic details with acceptable separation performance accuracy. From the review, it was found that the best performing ionic liquid membrane, mixed matrix membrane and functionalized hybrid membrane can enhance the performance of pristine membrane by 4 folds, 2.9 folds and 3.3 folds, respectively. The future prospects of molecular simulation in hybrid membranes are also presented. This review could provide understanding to the current advancement of molecular simulation approach in hybrid membranes separation. This could also provide a guideline to apply molecular simulation in the related sectors

Role of deep eutectic solvents as pretreatment medium for biomass transformation

Traditionally, biomass utilization was realized through the concept of biorefineries and the purpose of using biomass was mostly energy-driven. Over the years, the concept of biomass valorization shifted its focus toward unleashing the maximum potential of biomass in downstream processing such as for the production of various energy carriers and value-added bioproducts or chemicals. The main stepping stone toward realizing biomass transformation can be attributed to the ubiquitous nature of biomass, from which most of the biopolymers exhibited high recalcitrance in common solvents due to the heterogeneous polyphenolic structure of the lignin and the highly ordered cellulose’s crystalline structure. The recalcitrance of biomass poses constraints in the biomass-to-biofuels conversion or other valueadded bioproducts which typically involves three major steps: pretreatment, hydrolysis, and fermentation (Binod & Pandey, 2015). The pretreatment of biomass can be regarded as the most important step in biomass processing. In this sense, the goal of biomass pretreatment is to disintegrate the lignin barrier and make the celluloses, hemicelluloses, and other substrates accessible, as well as to enable the further processing and recovery of the valuable components embedded within the biomass

Role of deep eutectic solvents as pretreatment medium for biomass transformation

Traditionally, biomass utilization was realized through the concept of biorefineries and the purpose of using biomass was mostly energy-driven. Over the years, the concept of biomass valorization shifted its focus toward unleashing the maximum potential of biomass in downstream processing such as for the production of various energy carriers and value-added bioproducts or chemicals. The main stepping stone toward realizing biomass transformation can be attributed to the ubiquitous nature of biomass, from which most of the biopolymers exhibited high recalcitrance in common solvents due to the heterogeneous polyphenolic structure of the lignin and the highly ordered cellulose’s crystalline structure. The recalcitrance of biomass poses constraints in the biomass-to-biofuels conversion or other valueadded bioproducts which typically involves three major steps: pretreatment, hydrolysis, and fermentation (Binod & Pandey, 2015). The pretreatment of biomass can be regarded as the most important step in biomass processing. In this sense, the goal of biomass pretreatment is to disintegrate the lignin barrier and make the celluloses, hemicelluloses, and other substrates accessible, as well as to enable the further processing and recovery of the valuable components embedded within the biomass