NanoH2O, a manufacturer of cost effective reverse osmosis membranes for seawater desalination, has appointed global operations veteran, Doug Barnes as chief operating officer. The business is backed by Oak Investment Partners, Khosla Ventures, BASF Venture Capital, Total Energy Ventures International and Keytone Ventures.

San Francisco-based PapayaMobile, a social gaming network for the Android platform, has closed an $18 million Series B round. China’s Keytone Ventures and venture firm DCM provided the financing, which is aimed at expanding the company’s developer ecosystem in the U.S. and Europe. DCM funded the company’s initial $4 million round, closed in 2010. PapayaMobile has offices in Beijing and Menlo Park.

Keytone Ventures is raising up to $300 million for its second fund, according to a regulatory filing. MVision is serving as placement agent. The Beijing-based VC firm is run by former Kleiner Perkins pro Joe Zhou, and raised $200 million for its debut fund last year.

Keytone Ventures has closed its debut fund with $200 million in capital commitments. The China-focused firm’s principals are: Joe Zhou, formerly with KPCB China;Stella Jin, formerly with IDG-Accel China Growth Fund; and Peng Jin, also formerly with IDG-Accel China Growth Fund.

Keytone Ventures has secured $104 million in capital commitments for its debut fund, according to a regulatory filing. The firm was founded earlier this year by Joe Zhou, who previously led Chinese investment activities for Kleiner Perkins Caufield & Byers.