Publications de Christian Ludwig

Pt/Ce x Zr1-x O2 Bi-Functional Catalyst for Gas Recombination and Radical Scavenging in PEM Water Electrolysis Cells

Incorporating platinum (Pt) as a gas recombination catalyst in proton exchange membranes (PEMs) effectively addresses the challenge of pronounced hydrogen crossover in PEM water electrolysis cells, particularly when thin membranes are employed. However, th ...

AMER CHEMICAL SOC2025

Characterization of Biobased Polymers at the Gas-Solid Interface─Analysis of Surface and Bulk Properties during Artificial Degradation

Michel Rossi, Jeremy Luterbacher, Christian Ludwig, Tobias Borgmeyer

Accurately assessing the interfacial composition and reactivity of (bio)polymers under controlled but environmentally relevant conditions remains challenging. This study explores the evolution of surface functionalities of novel polyesters Poly(Butylene Xy ...

2025

Purification of Cellulose and Chitin Polymers and Other Value-Added Products from the Microalga Chlorella vulgaris Using a Green Biorefinery Process

Horst Pick, Christian Ludwig, Enio Daniel Zanchetta, Eya Nicodeme

Microalgae produce renewable biomass at high efficiency by using photosynthesis to capture the greenhouse gas CO2 from the atmosphere and releasing O2. Chlorella vulgaris is one of the most frequently cultivated unicellular green microalgae of commercial r ...

2025

Carbon-supported ZnO materials for sulfur capturing in supercritical water

Andrea Testino, Christian Ludwig

Sulfur (S) capturing materials working at supercritical water (SCW) conditions need to be designed and developed to overcome issues related with catalyst poisoning during the hydrothermal gasification of wet biomass, an efficient and sustainable technology ...

2025

From proof to practice − Sampling and analysis for simplified quantification of siloxanes in biogas

Christian Ludwig, Hossein Madi

Siloxanes in biogas pose significant challenges to energy systems, leading to operational inefficiencies and increased maintenance costs. This study advances the liquid quench sampling system (LQ) for accurate quantification of siloxanes using gas chromato ...

Elsevier2025

Recycling rare earth metals from luminescent fibers by solvent extraction

Christian Ludwig, Ajay Bhagwan Patil

Rare earth elements (REEs) are known for their specialized optical and electronic properties that have led to their use in a wide range of applications, such as luminescent fibers employed in security papers (e.g., bank notes). Most of the security documen ...

Elsevier BV2025

An Aerogel-Based Light-Driven Knudsen Pump Approaching Complete Passive Capturing of Airborne Particles in Wide Size Ranges

Christian Ludwig, Tianyu Cen

Aerosol sampling stands as an essential step in air quality monitoring and characterization. Active sampling provides accurate aerosol determination, while passive sampling offers cost-effective and power supply-free design. However, passive sampling is su ...

Elsevier BV2025

Abiotic stress approaches for enhancing cellulose and chitin production in Chlorella vulgaris

Horst Pick, Christian Ludwig, Enio Daniel Zanchetta, Eya Nicodeme

Several lines of evidence point to the presence of both, cellulose and chitin as structural constituents of the Chlorella vulgaris cell wall. These biopolymers are favourable building blocks for many sustainable industrial applications for instance as bioc ...

Elsevier BV2025

Continuous Supercritical Water Impregnation Method for the Preparation of Metal Oxide on Activated Carbon Composite Materials

Christian Ludwig

Metal oxide (MexOy) nanomaterials are used as catalysts and/or sorbents in processes taking place in supercritical water (scH2O), which is the “green” solvent needed to obtain energy-relevant products. Their properties are significantly influenced by the s ...

2024

Revealing the role of land-use features on macrolitter distribution in Swiss freshwaters

Christian Ludwig

Macrolitter, especially macroplastics, (> 0.5 cm) negatively impact freshwater ecosystems, where they can be retained along lake shores, riverbanks, floodplains or bed sediments. Long-term and large-scale assessments of macrolitter on riverbanks and lake s ...

Elsevier BV2024

Relating alkali release from a wood pellet with combustion progress: A modified random pore model supportive study

Christian Ludwig, Marco Wellinger, Rudolf Paul Wilhelm Jozef Struis

This paper concerns a miniature gasifier fed with a constant ambient-pressure flow of air to study the pyrolysis and subsequent combustion stage of a single wood pellet at T = 800 ℃. The alkali release and the concentration of simple gases were recorded si ...

EnPress Publisher2024

Dilution versus fractionation: Separation technologies hyphenated with spICP-MS for characterizing metallic nanoparticles in aerosols

Andrea Testino, Christian Ludwig, Jian Wang, Tianyu Cen

The presence of metal salts has become one of the major limitations for measuring metallic nanoparticles (NPs) in single particle inductively coupled plasma mass spectrometry (spICP-MS). Their presence generates a background signal in spICP-MS that can be ...

2024

Natural and simulated weathering of polystyrene: A molecular view of the polymeric interface

Michel Rossi, Florian Frédéric Vincent Breider, Christian Ludwig, Tobias Borgmeyer, Lu Zhou

This work presents the changing abundance of surface functional groups (SFGs) on polystyrene (PS) upon weathering within one or a few molecular monolayers from a molecular point of view. PS particles were aged by exposing it to a gas flow of typically (5 % ...

Elsevier BV2024

Rotating disk diluter hyphenated with single particle ICP-MS as an online dilution and sampling platform for metallic nanoparticles characterization in ambient aerosol

Andrea Testino, Christian Ludwig, Tianyu Cen

The application of single particle inductively coupled plasma mass spectrometry (spICP-MS) for online metallic nanoparticles (NPs) characterization in ambient aerosol remains a challenge. In this study, a hyphenated setup consisting of a rotating disk dilu ...

2024

Airborne metal nanoparticles released by azides detonation: determination and potential public exposure

Andrea Testino, Christian Ludwig, Tianyu Cen

Metal azides are highly energetic materials that release a large amount of gas upon detonation. They also release metal particles, generating an aerosol. The most common azide is sodium azide (NaN3), which is used nowadays in car airbags. If the decomposit ...

Springer Nature2024

Aerosol-into-liquid capture and detection of atmospheric soluble metals across the gas–liquid interface using Janus-membrane electrodes

Christian Ludwig, Jian Wang, Min Gao, Tianyu Cen

The soluble fraction of atmospheric transition metals is particularly associated with health effects such as reactive oxygen species compared to total metals. However, direct measurements of the soluble fraction are restricted to sampling and detection uni ...

2023

Surfactant-based enrichment of rare earth elements from NdFeB magnet e-waste: Optimisation of cloud formation and rare earths extraction

Christian Ludwig, Rudolf Paul Wilhelm Jozef Struis, Mohamed Tarik, Ajay Bhagwan Patil

Appropriate waste and resource management are essential for a sustainable circular economy with reduced environmental impact. With critical resources, e-waste may serve as indirect raw material. For example, with NdFeB permanent magnets, Neodymium (Nd) and ...

2023

Methods and devices for cultivating coenocytic algae

Christian Ludwig, Enio Daniel Zanchetta, Eya Nicodeme

The present invention concerns methods and devices for cultivating coenocytic algae and for producing cellulose, in particular microfibrillated cellulose (MFC). In one embodiment, the algae are grown on a solid substrate immersed in liquid culture medium. ...

2023

Insights about inductively coupled plasma optical emission spectroscopy interferences of major rare earth elements in complex e-waste feeds

Christian Ludwig, Rudolf Paul Wilhelm Jozef Struis, Mohamed Tarik, Ajay Bhagwan Patil

The advent of rare earth elements (REEs) with optoelectronic properties has shifted the technology paradigm from digital to a smart and hybrid world. Their substantial uses also resulted in a large piling up of e-waste. Therefore, e-waste is now a lucrativ ...

2022

Standard-Free Quantification of Dicarboxylic Acids: Case Studies with Salt-Rich Effluents and Serum

Christian Ludwig, Daniil Salionov, Sasa Bjelic

The present study evaluates the ionization efficiency (IE) of linear and branched C2–C14 dicarboxylic acids (DCAs) by electrospray ionization (ESI) under different conditions. The influence of the concentration of organic modifier (MeOH); mobile phase addi ...

2022