RESEARCH

Lignocellulosic waste (in this study municipal trimming) is a promising sustainable feedstock for ethanol production, but require costly and polluting pretreatment, that often result in toxic byproducts. Ozonation is a nonpolluting, effective pretreatment method, but is not used commercially due to the high energy requirements of the assumingly high ozone doses needed. Results demonstrated that both ozonation time and enzyme dose (at optimal pH) impact conversion efficiency to glucose. Ozonation (15 and 90 min, accumulated TOD=318 and 1114 mgO₃/L) of water-submerged waste (at pH=5.5) prior to enzyme addition at (×1.5 industrial enzyme dose) enabled high conversion of the cellulose fraction of the waste to glucose (31% and 42% respectively) compared to non-ozonated sample (with enzyme, 12%), suggesting ozonation could offer an effective and feasible pretreatment method. In these ozone doses, only 20% and 40% of the lignin was degraded showing that there is no need for delignification (as opposed to the common hypothesis) to obtain high sugar conversion. In addition, ozone process can be easily monitored by change in absorbance at 230, 280 and 436 nm, making it useful to use spectral scan in the field. Moreover, reduction in net calculated energy balance was obtained at higher ozone dose (90 min compared to 15 or 30 min), demonstrating increased process efficiency at lower ozone doses. Consequently, ozonation can be generated on-site and on demand, enabling decentralized pretreatment operated near the feed source thus overcoming transportation costs.

Crystalline nanocellulose (CNC) is a natural, renewable polymer which is composed of rod-like nanocrystals of cellulose with average dimensions of 100 nm in length and 5 nm in diameter. CNC possesses unique optical and mechanical properties, such as high aspect ratio, low density, high tensile strength, etc. Such properties make CNC a highly useful material for the manufacturing of various bioproducts. In recent years, interest in CNC intensifies as the industry realizes its potential, especially with its production being cheap and based on extraction from plants.

There are, however, several problems that arise by the production of crystalline nanocellulose from plants, such as a waste of water and the occupation of agricultural lands. An even more environmental production of CNC might be achieved by using recycled paper sludge (RPS) instead of plants, as RPS consists mainly of wood – which is very rich in cellulose as well.

The goal of this study is to try and develop an environmental-friendly method of producing CNC from RPS, while examining two approaches:

1. Chemical Hydrolysis: a hydrolysis using malic acid (di-carboxylic acid). Using such acid rather than the conventional use of phosphoric or sulfuric acid may add carboxylic groups to the cellulose, allowing higher electric charges and a better separation and recycling because it is a weak acid.
2. Enzymatic Hydrolysis: incubation with enzymes may prove highly effective for crystal utilization.

The next step of the research will be manufacturing membranes that are made of CNC, which will be produced from the RPS, for various water treatments such as an adsorption of dyes from textile industry or heavy metal ions from wastewater.  

Photocatalysis is a process which uses electromagnetic radiations (EMR) in order to activate catalysis and initiate the chemical reaction. Among all the various advanced oxidation processes it has found wider use from environment to energy application.

So how a photocatalyst Works?

Photocatalyst which is normally a semiconductors (metal oxides such as ZnO, TiO₂) with a particular electronic structure and when you irradiate with photons, energy greater than the band gap energy (E_g) of semiconductor excite electron (e^‑) from valence band (VB) to conduction band (CB) leaving this hole (h⁺) highly oxidised. So, if you have organic molecules (micropollutants) that are in contact with the hole it readily oxidise to CO₂ and minerals. The most important thing is to make sure the e^- and h⁺ are captured by the targeted molecules (pollutants) immediately, if not then they recombine and there will be no reaction and this is critical to design a good photocatalyst. Majority of work done till now are concentrated on material design. More than 85% of papers on photocatalysis that published are on making materials. We are less aware of surface reaction and process system. So, my contribution to the field is exploring and combining all together.

We are focused on designing visible light driven photocatalyst with high photon efficiency by reducing the recombination of electron–hole pairs with innovative chemistry design; we project our photocatalyst to treat water with natural sunlight instead of UV light and dramatically reduce costs for operators and to make antifouling self-cleaning materials for buildings and coating industries.

We’re also concerned to treat highly contaminated electroplating wastewater (WW) or any source with high loads of metals by using the indigenous metals in the WW as elements that enhance the process efficiency. This is a new and innovative concept in treatment of WW where the metal contaminants participate and accelerate the process for advancing their subsequent removal as well as other contaminants. A novel hybrid process is designed for accelerating visible light catalytic processes by the oxidized/reduced indigenous metals for targeting their removal and other contaminates and utilizes the metals in the sludge as accelerators in enhancing biofuels and biofertilizers yield from metallurgical industry waste water expeditiously. 

Plastic fragments from various sizes polluting the ocean are increasing significantly each year, having a devastating effect on the marine environment. Efforts are directed toward estimating the amount of plastic and micro-plastic present in the ocean and studying its impact on marine ecosystems. A major problem that negatively affects marine organisms, caused by plastic residues, is the release of phthalates to the aquatic phase. 

Ascidians are marine filter-feeding invertebrates of the phylum Chordata, which are very common around the world. Being immobile and able to filter high volumes of water, ascidians have a unique potential to act as a natural biological filter for micro-plastic suspended in the water column and bioaccumulation of phthalates released inside the organisms’ body.

An innovative analytical method was developed for the detection and quantification of phthalates in ascidians soft tissue. This method is based on the extraction of phthalates from tissues using Accelerated Solvent Extractor (ASE), and GC/MS for detection and quantification. The results indicate large quantities of phthalates in the organisms' body, much more than reported on similar studies in the past and demonstrating some differences between independent sampling sites.